Description
Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests.
This issue affects Apache HTTP Server: from 2.4.17 through 2.4.67.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache HTTP Server | 2.4.17 – ≤ 2.4.67 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | apache2 | 2.4.67-2 | — |
| Debian 13 | apache2 | 2.4.67-1~deb13u3 | — |
| Debian 12 | apache2 | 2.4.67-1~deb12u3 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | apache2 | 2.4.66-2ubuntu2.2 | — |
| Ubuntu 26.04 LTS | nginx | 1.28.3-2ubuntu1.5 | — |
| Ubuntu 25.10 | apache2 | 2.4.64-1ubuntu3.5 | — |
| Ubuntu 25.10 | nginx | 1.28.0-6ubuntu1.7 | — |
| Ubuntu 24.04 LTS | apache2 | 2.4.58-1ubuntu8.13 | — |
| Ubuntu 24.04 LTS | nginx | 1.24.0-2ubuntu7.12 | — |
| Ubuntu 22.04 LTS | apache2 | 2.4.52-1ubuntu4.21 | — |
| Ubuntu 22.04 LTS | nginx | 1.18.0-6ubuntu14.15 | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | apache2 | 2.4.41-4ubuntu3.23+esm5 | USN-8571-1 |
| Ubuntu Pro 20.04 LTS | nginx | 1.18.0-0ubuntu1.7+esm3 | — |
| Ubuntu Pro 18.04 LTS | apache2 | 2.4.29-1ubuntu4.27+esm10 | USN-8571-1 |
| Ubuntu Pro 18.04 LTS | nginx | 1.14.0-0ubuntu1.11+esm4 | — |
| Ubuntu Pro 16.04 LTS | apache2 | 2.4.18-2ubuntu3.17+esm19 | USN-8571-1 |
| Ubuntu Pro 16.04 LTS | nginx | 1.10.3-0ubuntu0.16.04.5+esm9 | — |
| Ubuntu Pro 14.04 LTS | apache2 | 2.4.7-1ubuntu4.22+esm14 | USN-8571-1 |
| Ubuntu Pro 14.04 LTS | nginx | 1.4.6-1ubuntu3.9+esm8 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | mod_http2 | 2.0.29-4.el10_2.1 | RHSA-2026:25225 |
| RHEL 9 | mod_http2 | 2.0.26-6.el9_8.1 | RHSA-2026:25057 |
| RHEL 8 | httpd +6 | 2.4.37-65.module+el8.10.0+24281+ea10630c.8 | RHSA-2026:25090 |
| RHEL 8 | mod_http2 | 1.15.7-10.module+el8.10.0+24368+ad388a0c.6 | RHSA-2026:25090 |
| RHEL 8 | mod_md | 1:2.0.8-8.module+el8.10.0+23815+1b5e1c66.2 | RHSA-2026:25090 |
| RHEL 8 | mod_ssl +1 | 1:2.4.37-65.module+el8.10.0+24281+ea10630c.8 | RHSA-2026:25090 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.0 EUS | mod_http2 | 2.0.29-2.el10_0.2 | RHSA-2026:50538 |
| RHEL 9.6 EUS | mod_http2 | 2.0.26-4.el9_6.2 | RHSA-2026:50572 |
| RHEL 9.4 E4S | mod_http2 | 2.0.26-2.el9_4.3 | RHSA-2026:55992 |
| RHEL 9.2 E4S | mod_http2 | 1.15.19-4.el9_2.8 | RHSA-2026:55930 |
| RHEL 8.8 TUS | httpd +6 | 2.4.37-56.module+el8.8.0+24497+e470c0e2.12 | RHSA-2026:36373 |
| RHEL 8.8 TUS | mod_http2 | 1.15.7-8.module+el8.8.0+24497+e470c0e2.7 | RHSA-2026:36373 |
| RHEL 8.8 TUS | mod_md | 1:2.0.8-8.module+el8.8.0+23840+d7e7db80.1 | RHSA-2026:36373 |
| RHEL 8.8 TUS | mod_ssl +1 | 1:2.4.37-56.module+el8.8.0+24497+e470c0e2.12 | RHSA-2026:36373 |
| RHEL 8.8 E4S | httpd +6 | 2.4.37-56.module+el8.8.0+24497+e470c0e2.12 | RHSA-2026:36373 |
| RHEL 8.8 E4S | mod_http2 | 1.15.7-8.module+el8.8.0+24497+e470c0e2.7 | RHSA-2026:36373 |
| RHEL 8.8 E4S | mod_md | 1:2.0.8-8.module+el8.8.0+23840+d7e7db80.1 | RHSA-2026:36373 |
| RHEL 8.8 E4S | mod_ssl +1 | 1:2.4.37-56.module+el8.8.0+24497+e470c0e2.12 | RHSA-2026:36373 |
| RHEL 8.6 EUS Long Life | httpd +6 | 2.4.37-47.module+el8.6.0+24496+af8fe930.13 | RHSA-2026:36831 |
| RHEL 8.6 EUS Long Life | mod_http2 | 1.15.7-5.module+el8.6.0+24496+af8fe930.5 | RHSA-2026:36831 |
| RHEL 8.6 EUS Long Life | mod_md | 1:2.0.8-8.module+el8.6.0+23843+c27a5dc4.1 | RHSA-2026:36831 |
| RHEL 8.6 EUS Long Life | mod_ssl +1 | 1:2.4.37-47.module+el8.6.0+24496+af8fe930.13 | RHSA-2026:36831 |
| RHEL 8.6 AUS | httpd +6 | 2.4.37-47.module+el8.6.0+24496+af8fe930.13 | RHSA-2026:36831 |
| RHEL 8.6 AUS | mod_http2 | 1.15.7-5.module+el8.6.0+24496+af8fe930.5 | RHSA-2026:36831 |
| RHEL 8.6 AUS | mod_md | 1:2.0.8-8.module+el8.6.0+23843+c27a5dc4.1 | RHSA-2026:36831 |
| RHEL 8.6 AUS | mod_ssl +1 | 1:2.4.37-47.module+el8.6.0+24496+af8fe930.13 | RHSA-2026:36831 |
| RHEL 8.4 EUS Long Life | httpd +6 | 2.4.37-39.module+el8.4.0+24495+1afced82.12 | RHSA-2026:36846 |
| RHEL 8.4 EUS Long Life | mod_http2 | 1.15.7-3.module+el8.4.0+24495+1afced82.5 | RHSA-2026:36846 |
| RHEL 8.4 EUS Long Life | mod_md | 1:2.0.8-8.module+el8.4.0+23842+00253415.1 | RHSA-2026:36846 |
| RHEL 8.4 EUS Long Life | mod_ssl +1 | 1:2.4.37-39.module+el8.4.0+24495+1afced82.12 | RHSA-2026:36846 |
| RHEL 8.4 AUS | httpd +6 | 2.4.37-39.module+el8.4.0+24495+1afced82.12 | RHSA-2026:36846 |
| RHEL 8.4 AUS | mod_http2 | 1.15.7-3.module+el8.4.0+24495+1afced82.5 | RHSA-2026:36846 |
| RHEL 8.4 AUS | mod_md | 1:2.0.8-8.module+el8.4.0+23842+00253415.1 | RHSA-2026:36846 |
| RHEL 8.4 AUS | mod_ssl +1 | 1:2.4.37-39.module+el8.4.0+24495+1afced82.12 | RHSA-2026:36846 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-httpd +6 | 2.4.62-13.el7jbcs | RHSA-2026:27200 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_http2 | 2.0.29-10.el7jbcs | RHSA-2026:27200 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_md | 1:2.4.28-16.el7jbcs | RHSA-2026:27200 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_ssl +1 | 1:2.4.62-13.el7jbcs | RHSA-2026:27200 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-nghttp2 +1 | 1.64.0-3.el7jbcs | RHSA-2026:27200 |
| Red Hat Hardened Images 1 | httpd +5 | 2.4.68-1.hum1 | RHSA-2026:25042 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | mod_http2 | 2.0.29-4.el10_2.1 | ALSA-2026:25225 |
| AlmaLinux 9 | mod_http2 | 2.0.26-6.el9_8.1 | ALSA-2026:25057 |
| AlmaLinux 8 | httpd +6 | 2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:25090 |
| AlmaLinux 8 | mod_http2 | 1.15.7-10.module_el8.10.0+4190+704ad79b.6 | ALSA-2026:25090 |
| AlmaLinux 8 | mod_md | 1:2.0.8-8.module_el8.10.0+4088+57f011c1.2 | ALSA-2026:25090 |
| AlmaLinux 8 | mod_ssl +1 | 1:2.4.37-65.module_el8.10.0+4185+0955a0d7.8 | ALSA-2026:25090 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | mod_http2 | 2.0.29-4.el10_2.1 | RLSA-2026:25225 |
| Rocky Linux 9 | mod_http2 | 2.0.26-6.el9_8.1 | RLSA-2026:25057 |
| Rocky Linux 8 | httpd | 2.4.37-65.module+el8.10.0+1830+22f0c9e0 | RLSA-2026:25090 |
| Rocky Linux 8 | mod_http2 | 1.15.7-10.module+el8.10.0+1775+6b057638 | RLSA-2026:25090 |
| Rocky Linux 8 | mod_md | 1:2.0.8-8.module+el8.9.0+1370+89cc8ad5 | RLSA-2026:25090 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | apache2 +6 | 2.4.66-150700.4.23.1 | SUSE-SU-2026:2759-1 |
| SLES 15 SP6 | apache2 +5 | 2.4.66-150600.5.55.1 | SUSE-SU-2026:2735-1 |
| SLES 15 SP5 | apache2 | 2.4.66-150400.6.57.1 | SUSE-SU-2026:2686-1 |
| SLES 15 SP4 | apache2 | 2.4.66-150400.6.57.1 | SUSE-SU-2026:2686-1 |
| SLES 12 SP5 | apache2 +1 | 2.4.66-35.81.1 | SUSE-SU-2026:2717-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | apache2 +6 | 2.4.66-160000.3.1 | SUSE-SU-2026:22564-1 |
| SLES for SAP 15 SP6 | apache2 +5 | 2.4.66-150600.5.55.1 | SUSE-SU-2026:2735-1 |
| SLES for SAP 15 SP5 | apache2 | 2.4.66-150400.6.57.1 | SUSE-SU-2026:2686-1 |
| SLES for SAP 15 SP4 | apache2 | 2.4.66-150400.6.57.1 | SUSE-SU-2026:2686-1 |
| SLES 16.0 | apache2 +6 | 2.4.66-160000.3.1 | SUSE-SU-2026:22564-1 |
| SLE HPC 15 SP5 | apache2 | 2.4.66-150400.6.57.1 | SUSE-SU-2026:2686-1 |
| SLE HPC 15 SP4 | apache2 | 2.4.66-150400.6.57.1 | SUSE-SU-2026:2686-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | apache2 +6 | 2.4.66-160000.3.1 | openSUSE-SU-2026:21235-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | apache2 | 2.4.68-r0 | — |
| Alpine v3.24 | nginx | 1.30.1-r0 | — |
| Alpine v3.23 | apache2 | 2.4.68-r0 | — |
| Alpine v3.23 | nginx | 1.28.3-r3 | — |
| Alpine v3.22 | apache2 | 2.4.68-r0 | — |
| Alpine v3.22 | nginx | 1.28.3-r3 | — |
| Alpine v3.21 | apache2 | 2.4.68-r0 | — |
| Alpine v3.21 | nginx | 1.26.3-r1 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | mod_http2 | 2.0.42-1.amzn2023.0.1 | ALAS2023-2026-1859 |
| Amazon Linux 2 | mod_http2 | 2.0.42-1.amzn2.0.1 | ALAS2-2026-3372 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | httpd | 2.4.68-1 | — |
| Azure Linux 3 | mod_http2 | No fix yet | — |
| Azure Linux 3 | nginx | 1.28.3-5 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | mod_http2 | 2.0.29-4.el10_2.2 | ELSA-2026-25225 |
| Oracle Linux 9 | mod_http2 | 2.0.26-6.el9_8.1 | ELSA-2026-25057 |
| Oracle Linux 8 | httpd +6 | 2.4.37-65.0.1.module+el8.10.0+90909+2fc0e3ca.8 | ELSA-2026-25090 |
| Oracle Linux 8 | mod_http2 | 1.15.7-10.module+el8.10.0+90909+2fc0e3ca.6 | ELSA-2026-25090 |
| Oracle Linux 8 | mod_md | 1:2.0.8-8.module+el8.10.0+90899+db89cbcc.2 | ELSA-2026-25090 |
| Oracle Linux 8 | mod_ssl +1 | 1:2.4.37-65.0.1.module+el8.10.0+90909+2fc0e3ca.8 | ELSA-2026-25090 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 13 repositories · most starred shown
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mrx-arafat/CVE-2026-49975-POC ★ 30 · Jun 4, 2026
HTTP/2 Bomb PoC — CVE-2026-49975 (HPACK indexed reference bomb + flow-control stall)
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EQSTLab/CVE-2026-49975 ★ 14 · Jun 10, 2026
HTTP/2 Bomb
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LSG-PolarBear/CVE-2026-49975 ★ 6 · Jun 10, 2026
CVE-2026-49975漏洞复现
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fevar54/Proof-of-Concept-POC---CVE-2026-49975-HTTP-2-Bomb- ★ 6 · Jun 3, 2026
PoC de CVE-2026-49975 (HTTP/2 Bomb): DoS remoto contra servidores web con HTTP/2 por defecto.
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naheeju/POC-CVE-2026-49975 ★ 3 · Sep 16, 2026
Security research PoC for CVE-2026-49975: HTTP/2 HPACK compression bomb + flow-control hold DoS in Apache mod_http2
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LiaoZiqi-GZFLS/CVE-2026-49975 ★ 3 · Jun 10, 2026
CVE-2026-49975
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razureink/cve-2026-49975-http2bomb_reproduction ★ 2 · Jun 13, 2026
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renzi25031469/CVE-2026-49975-HTTP-2-Bomb ★ 2 · Jun 8, 2026
Disclosed on June 3, 2026, the "HTTP/2 Bomb" is an unauthenticated remote DoS that combines an HPACK compression bomb with a Slowloris-style hold to exhaust server memory. It affects default HTTP/2 c…
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yym8538/CVE-2026-49975 ★ 1 · Aug 21, 2026
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minc-nice-100/http2-bomb-analysis-paper ★ 1 · Jun 13, 2026
HTTP/2 Bomb: HPACK indexed-reference amplification + flow-control stall. A high school student's full protocol analysis (LaTeX). CVE-2026-49975, CVE-2026-47774.
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 34
- WID-SEC-2026-2455 Oracle Solaris Drittanbieterkomponenten: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- WID-SEC-2026-1824 Apache HTTP Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 11, 2026
- WID-SEC-2026-1791 HTTP/2-Implementierungen: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Nov 9, 2026
- WID-SEC-2026-3595 IBM QRadar SIEM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 2, 2026
- ALSA-2026:25057 Important: mod_http2 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:25225 Important: mod_http2 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:25090 Important: httpd:2.4 security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2026:27200 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP4 security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:55992 Red Hat Security Advisory: mod_http2 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:55930 Red Hat Security Advisory: mod_http2 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:50538 Red Hat Security Advisory: mod_http2 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:50572 Red Hat Security Advisory: mod_http2 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:36846 Red Hat Security Advisory: httpd:2.4 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:36831 Red Hat Security Advisory: httpd:2.4 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:36373 Red Hat Security Advisory: httpd:2.4 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:25225 Red Hat Security Advisory: mod_http2 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:25057 Red Hat Security Advisory: mod_http2 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:25090 Red Hat Security Advisory: httpd:2.4 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:25042 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- USN-8571-1 apache2 vulnerabilities Ubuntu Security Notices (USN) · Jul 21, 2026
- ELSA-2026-25225 Important: mod_http2 security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jul 20, 2026
- SUSE-SU-2026:22564-1 Security update for apache2 SUSE / openSUSE Security Updates · Jul 15, 2026
- openSUSE-SU-2026:21235-1 Security update for apache2 SUSE / openSUSE Security Updates · Jul 9, 2026
- SUSE-SU-2026:2759-1 Security update for apache2 SUSE / openSUSE Security Updates · Jul 7, 2026
- SUSE-SU-2026:2735-1 Security update for apache2 SUSE / openSUSE Security Updates · Jul 4, 2026
- SUSE-SU-2026:2717-1 Security update for apache2 SUSE / openSUSE Security Updates · Jul 2, 2026
- SUSE-SU-2026:2686-1 Security update for apache2 SUSE / openSUSE Security Updates · Jul 1, 2026
- ELSA-2026-25057 Important: mod_http2 security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jun 23, 2026
- ALAS2-2026-3372 Important: mod_http2 security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jun 22, 2026
- ALAS2023-2026-1859 Important: mod_http2 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Jun 22, 2026
- ELSA-2026-25090 Important: httpd:2.4 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jun 17, 2026
- RLSA-2026:25057 Important: mod_http2 security update Rocky Linux Security Advisories · Jun 13, 2026
- RLSA-2026:25225 Important: mod_http2 security update Rocky Linux Security Advisories · Jun 13, 2026
- RLSA-2026:25090 Important: httpd:2.4 security update Rocky Linux Security Advisories · Jun 11, 2026
References
- https://httpd.apache.org/security/vulnerabilities_24.html vendor-advisory