Description
Issue summary: When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42)
peer key, the peer key is not properly checked for the subgroup membership.
Impact summary: A malicious peer which presents an X9.42 key carrying the
victim's p and g parameters, a forged q = r (a small prime factor of the
cofactor (p−1)/q_local), and a public value Y of order r can recover the
victim's private key after a small number of key exchange attempts.
When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the
subgroup membership check Y^q ≡ 1 (mod p) is performed using the peer's
own q parameter, not the local key's q. The peer's domain parameters are
then matched against the domain parameters of the private key, but the value
of q is not compared.
A malicious peer who presents an X9.42 key carrying the victim's p, g,
a forged q = r (a small prime factor of the cofactor), and a public
value Y of order r passes all checks. The shared secret then takes only
r distinct values, leaking priv mod r. Repeating for each small-prime
factor of the cofactor and combining via CRT recovers the full private
key (Lim–Lee / small-subgroup-confinement attack).
The realistic attack surface is narrow: principally CMP deployments with
long-lived RA/CA DHX keys and bespoke enterprise or government applications
using X9.42 DHX static keys with interactive protocols and therefore this
issue was assigned Low severity.
The FIPS modules in 4.0, 3.6, 3.5, 3.4, 3.1.2 and 3.0 are affected by this
issue.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| OpenSSL | OpenSSL | 4.0.0 – < 4.0.1, 3.6.0 – < 3.6.3, 3.5.0 – < 3.5.7, 3.4.0 – < 3.4.6, 3.0.0 – < 3.0.21 | 4.0.1 |
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 | openssl | 3.6.3-1 | — |
| Debian 13 | openssl | 3.5.6-1~deb13u2 | — |
| Debian 12 | openssl | 3.0.20-1~deb12u2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | edk2 +1 | No fix yet | — |
| Ubuntu 26.04 LTS | edk2 +1 | No fix yet | — |
| Ubuntu 26.04 LTS | openssl | 3.5.5-1ubuntu3.2 | — |
| Ubuntu 25.10 | edk2 | No fix yet | — |
| Ubuntu 25.10 | openssl | 3.5.3-1ubuntu3.4 | — |
| Ubuntu 24.04 LTS | edk2 | No fix yet | — |
| Ubuntu 24.04 LTS | openssl | 3.0.13-0ubuntu3.11 | — |
| Ubuntu 22.04 LTS | openssl | 3.0.2-0ubuntu1.25 | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro FIPS-updates 24.04 LTS | openssl-fips | 3.0.13-0ubuntu3.12+Fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | openssl | 3.0.2-0ubuntu1.25+Fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | openssl-fips | No fix yet | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | openssl +1 | No fix yet | — |
| Ubuntu Pro 22.04 LTS | nodejs | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | openssl +3 | 1:3.5.5-4.el10_2 | RHSA-2026:25237 |
| RHEL 9 | openssl +3 | 1:3.5.5-4.el9_8 | RHSA-2026:25239 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | bootupd +1 | 0.3.2-1.hum1 | RHSA-2026:67551 |
| Red Hat Hardened Images 1 | chunkah | 0.6.0-3.hum1 | RHSA-2026:42825 |
| Red Hat Hardened Images 1 | openssl +10 | 1:3.5.8-0.1.hum1 | RHSA-2026:59641, RHSA-2026:59635 |
| Red Hat Hardened Images 1 | python-cryptography +1 | 50.0.0-1.hum1 | RHSA-2026:55543 |
| Red Hat Hardened Images 1 | ruby3.3 +5 | 3.3.10-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | ruby3.4 +5 | 3.4.10-31.7.hum1 | RHSA-2026:62790 |
| Red Hat Hardened Images 1 | ruby4.0 +5 | 4.0.6-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem3.3-bigdecimal | 3.1.5-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-bundler | 2.5.22-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-devel +1 | 3.5.22-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-io-console | 0.7.1-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-irb | 1.13.1-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-json | 2.7.2-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-minitest | 5.20.0-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-power_assert | 2.0.3-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-psych | 5.1.2-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-racc | 1.7.3-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-rake | 13.1.0-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-rbs | 3.4.0-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-rdoc | 6.6.3.1-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-rexml | 3.4.4-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-rss | 0.3.1-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-test-unit | 3.6.1-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem3.3-typeprof | 0.21.9-23.6.hum1 | RHSA-2026:62562 |
| Red Hat Hardened Images 1 | rubygem4.0-bigdecimal | 4.0.1-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-devel +2 | 4.0.16-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-io-console | 0.8.2-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-irb | 1.16.0-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-json | 2.18.0-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-minitest | 6.0.0-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-power_assert | 3.0.1-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-psych | 5.3.1-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-racc | 1.8.1-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-rake | 13.3.1-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-rbs | 3.10.0-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-rdoc | 7.0.4-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-rexml | 3.4.4-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-rss | 0.3.2-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-test-unit | 3.7.5-37.3.hum1 | RHSA-2026:62563 |
| Red Hat Hardened Images 1 | rubygem4.0-typeprof | 0.31.1-37.3.hum1 | RHSA-2026:62563 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | openssl +3 | 1:3.5.5-4.el10_2.alma.1 | ALSA-2026:25237 |
| AlmaLinux 9 | openssl +3 | 1:3.5.5-4.el9_8 | ALSA-2026:25239 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | openssl | 1:3.5.5-4.el10_2 | RLSA-2026:25237 |
| Rocky Linux 9 | openssl | 1:3.5.5-4.el9_8 | RLSA-2026:25239 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | openssl-3 | 3.2.3-150700.5.36.1 | SUSE-SU-2026:2648-1 |
| SLES 15 SP6 | openssl-3 | 3.1.4-150600.5.53.1 | SUSE-SU-2026:2393-1 |
| SLES 15 SP5 | openssl-3 | 3.0.8-150500.5.66.1 | SUSE-SU-2026:2397-1 |
| SLES 15 SP4 | openssl-3 | 3.0.8-150400.4.87.1 | SUSE-SU-2026:2598-1 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | openssl-3 | 3.5.0-160000.8.1 | SUSE-SU-2026:22315-1 |
| SLES for SAP 15 SP6 | openssl-3 | 3.1.4-150600.5.53.1 | SUSE-SU-2026:2393-1 |
| SLES for SAP 15 SP5 | openssl-3 | 3.0.8-150500.5.66.1 | SUSE-SU-2026:2397-1 |
| SLES for SAP 15 SP4 | openssl-3 | 3.0.8-150400.4.87.1 | SUSE-SU-2026:2598-1 |
| SLES 16.0 | openssl-3 | 3.5.0-160000.8.1 | SUSE-SU-2026:22315-1 |
| SLE Micro 6.2 | openssl-3 | 3.5.0-160000.8.1 | SUSE-SU-2026:22251-1 |
| SLE Micro 6.1 | openssl-3 | 3.1.4-slfo.1.1_10.1 | SUSE-SU-2026:22132-1 |
| SLE Micro 6.0 | openssl-3 | 3.1.4-14.1 | SUSE-SU-2026:22100-1 |
| SLE Micro 5.4 | openssl-3 | 3.0.8-150400.4.87.1 | SUSE-SU-2026:2598-1 |
| SLE Micro 5.3 | openssl-3 | 3.0.8-150400.4.87.1 | SUSE-SU-2026:2598-1 |
| SLE HPC 15 SP5 | openssl-3 | 3.0.8-150500.5.66.1 | SUSE-SU-2026:2397-1 |
| SLE HPC 15 SP4 | openssl-3 | 3.0.8-150400.4.87.1 | SUSE-SU-2026:2598-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | openssl-3 | 3.5.3-6.1 | openSUSE-SU-2026:11023-1 |
| openSUSE Leap 16.0 | openssl-3 | 3.5.0-160000.8.1 | openSUSE-SU-2026:21005-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | openssl | 3.5.7-r0 | — |
| Alpine v3.23 | openssl | 3.5.7-r0 | — |
| Alpine v3.22 | openssl | 3.5.7-r0 | — |
| Alpine v3.21 | openssl | 3.3.7-r1 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | openssl +5 | 1:3.5.5-1.amzn2023.0.5 | ALAS2023-2026-1853 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | edk2 | 20240524git3e722403cd16-20 | — |
| Azure Linux 3 | openssl | 3.3.7-4 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | openssl +3 | 1:3.5.5-5.0.1.el10_2 | ELSA-2026-25237 |
| Oracle Linux 9 | openssl +3 | 1:3.5.5-4.0.1.el9_8 | ELSA-2026-50379, ELSA-2026-25239 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | openssl +1 | 3.6.3-r0 | — |
| Wolfi rolling | openssl-4.0 +2 | 4.0.1-r0 | — |
Advisories 31
- RHSA-2026:59635 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:59641 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- WID-SEC-2026-2455 Oracle Solaris Drittanbieterkomponenten: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- WID-SEC-2026-1852 OpenSSL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 11, 2026
- ALSA-2026:25239 Important: openssl security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:25237 Important: openssl security update AlmaLinux Security Advisories · Oct 29, 2026
- WID-SEC-2026-2919 IBM App Connect Enterprise: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 27, 2026
- RHSA-2026:67551 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:62790 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:62562 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:62563 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:55543 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:42825 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:25239 Red Hat Security Advisory: openssl security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:25237 Red Hat Security Advisory: openssl security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- ELSA-2026-25237 Important: openssl security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jul 28, 2026
- ELSA-2026-50379 Moderate: openssl security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jul 7, 2026
- SUSE-SU-2026:22315-1 Security update for openssl-3 SUSE / openSUSE Security Updates · Jul 2, 2026
- openSUSE-SU-2026:21005-1 Security update for openssl-3 SUSE / openSUSE Security Updates · Jun 30, 2026
- SUSE-SU-2026:22251-1 Security update for openssl-3 SUSE / openSUSE Security Updates · Jun 30, 2026
- SUSE-SU-2026:2648-1 Security update for openssl-3 SUSE / openSUSE Security Updates · Jun 27, 2026
- SUSE-SU-2026:2598-1 Security update for openssl-3 SUSE / openSUSE Security Updates · Jun 24, 2026
- ELSA-2026-25239 Important: openssl security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jun 23, 2026
- ALAS2023-2026-1853 Important: openssl security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Jun 22, 2026
- SUSE-SU-2026:22132-1 Security update for openssl-3 SUSE / openSUSE Security Updates · Jun 18, 2026
- SUSE-SU-2026:22100-1 Security update for openssl-3 SUSE / openSUSE Security Updates · Jun 17, 2026
- SUSE-SU-2026:2393-1 Security update for openssl-3 SUSE / openSUSE Security Updates · Jun 16, 2026
- SUSE-SU-2026:2397-1 Security update for openssl-3 SUSE / openSUSE Security Updates · Jun 16, 2026
- openSUSE-SU-2026:11023-1 libopenssl-3-devel-3.5.3-6.1 on GA media SUSE / openSUSE Security Updates · Jun 14, 2026
- RLSA-2026:25237 Important: openssl security update Rocky Linux Security Advisories · Jun 13, 2026
- RLSA-2026:25239 Important: openssl security update Rocky Linux Security Advisories · Jun 13, 2026
References
- OpenSSL Advisory vendor-advisory
- 4.0.1 git commit patch
- 3.6.3 git commit patch
- 3.5.7 git commit patch
- 3.4.6 git commit patch
- 3.0.21 git commit patch