Description
This vulnerability allows remote attackers to deny service on vulnerable installations of The Squid Software Foundation Squid 3.5.27-20180318. Authentication is not required to exploit this vulnerability. The specific flaw exists within ClientRequestContext::sslBumpAccessCheck(). A crafted request can trigger the dereference of a null pointer. An attacker can leverage this vulnerability to create a denial-of-service condition to users of the system. Was ZDI-CAN-6088.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| The Squid Software Foundation | The Squid Software Foundation Squid | 3.5.27-20180318 | — |
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 | squid | 4.1-1 | — |
| Debian 13 | squid | 4.1-1 | — |
| Debian 12 | squid | 4.1-1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | squid | 3.5.21-26.9.1 | SUSE-SU-2018:1122-1 |
| SLES 11 SP4 | squid3 | 3.1.23-8.16.37.6.1 | SUSE-SU-2018:1365-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP3 | squid | 3.5.21-26.9.1 | SUSE-SU-2018:1122-1 |
| SLES for SAP 11 SP4 | squid3 | 3.1.23-8.16.37.6.1 | SUSE-SU-2018:1365-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | squid | 4.16-1.5 | openSUSE-SU-2024:11403-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | squid | 3.5.27-r2 | — |
| Alpine v3.23 | squid | 3.5.27-r2 | — |
| Alpine v3.22 | squid | 3.5.27-r2 | — |
| Alpine v3.21 | squid | 3.5.27-r2 | — |
| Alpine v3.20 | squid | 3.5.27-r2 | — |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | squid | 3.5.27-r2 | — |
| Alpine v3.18 | squid | 3.5.27-r2 | — |
| Alpine v3.17 | squid | 3.5.27-r2 | — |
| Alpine v3.16 | squid | 3.5.27-r2 | — |
| Alpine v3.15 | squid | 3.5.27-r2 | — |
| Alpine v3.14 | squid | 3.5.27-r2 | — |
| Alpine v3.13 | squid | 3.5.27-r2 | — |
| Alpine v3.12 | squid | 3.5.27-r2 | — |
| Alpine v3.11 | squid | 3.5.27-r2 | — |
| Alpine v3.10 | squid | 3.5.27-r2 | — |
| Alpine v3.9 | squid | 3.5.27-r2 | — |
| Alpine v3.8 | squid | 3.5.27-r2 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | squid +2 | 7:3.5.20-15.amzn2.1.1 | ALAS2-2020-1486 |
Advisories 4
- SUSE-SU-2018:1122-1 security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:11403-1 squid-4.16-1.5 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:1365-1 Security update for squid3 SUSE / openSUSE Security Updates · Feb 4, 2026
- ALAS2-2020-1486 Moderate: squid security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Sep 2, 2020