VulnerabilityPublished 9 Nov 2026

CVE-2026-61642: Important · squid:4 security update

Affects libecapSource GCVE Database

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Authoritative record:CVE-2026-61642· High 7.7

Not known to be exploited · CVSS 7.7 High · fixed in 1.0.1-2.module_el8.6.0+2741+01592ae8 : patch libecap soon.

Data as of 9 Nov 2026, 15:50 UTC

CVSS 3.1 base score

7.7High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 1.0.1-2.module_el8.6.0+2741+01592ae8, 1.0.1-2.module_el8.6.0+3048+383bc947, 7:4.15-10.module_el8.10.0+4354+d3ed158a.13

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Changed
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

almalinux-8

What to do

Upgrade the AlmaLinux to 1.0.1-2.module_el8.6.0+2741+01592ae8 (libecap package, libecap-devel package) or 1.0.1-2.module_el8.6.0+3048+383bc947 (libecap package, libecap-devel package) or 7:4.15-10.module_el8.10.0+4354+d3ed158a.13 (squid package).

Patches and advisories

access.redhat.com/errata/RHSA-2026:96078 (opens in a new tab)

Affected software

Product	Affected	Fixed in
AlmaLinux 8libecap	Affected <1.0.1-2.module_el8.6.0+2741+01592ae8	Fixed in 1.0.1-2.module_el8.6.0+2741+01592ae8
AlmaLinux 8libecap	Affected <1.0.1-2.module_el8.6.0+3048+383bc947	Fixed in 1.0.1-2.module_el8.6.0+3048+383bc947
AlmaLinux 8libecap-devel	Affected <1.0.1-2.module_el8.6.0+2741+01592ae8	Fixed in 1.0.1-2.module_el8.6.0+2741+01592ae8
AlmaLinux 8libecap-devel	Affected <1.0.1-2.module_el8.6.0+3048+383bc947	Fixed in 1.0.1-2.module_el8.6.0+3048+383bc947
AlmaLinux 8squid	Affected <7:4.15-10.module_el8.10.0+4354+d3ed158a.13	Fixed in 7:4.15-10.module_el8.10.0+4354+d3ed158a.13

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A security update fixing CVE-2026-61642 is available and should be applied. Red Hat has released patched versions of Squid and libecap for Red Hat Enterprise Linux 8. Users should update to the fixed versions: 1.0.1-2.module_el8.6.0+2741+01592ae8 or later for libecap and 7:4.15-10.module_el8.10.0+4354+d3ed158a.13 or later for Squid. Follow the vendor's update instructions at https://access.redhat.com/articles/11258. No additional mitigation steps are indicated by the vendor.

Description

A security vulnerability identified as CVE-2026-61642 affects Squid, a high-performance proxy caching server. The issue involves HTTP request smuggling via the Transfer-Encoding header. This vulnerability has been addressed in updated versions of Squid and related libecap packages. The fix is available and has been released by Red Hat for multiple architectures and versions of Red Hat Enterprise Linux 8. No known exploits in the wild have been reported.

Impact

The vulnerability allows HTTP request smuggling, which can lead to HTTP request interference and potentially impact the security and integrity of web traffic handled by Squid proxies. The Red Hat advisory rates the security impact as Important. There are no reports of exploitation in the wild at this time.

Summary

CVE-2026-61642 is a request smuggling vulnerability in Squid's handling of the HTTP Transfer-Encoding header. This flaw could allow an attacker to interfere with the processing of HTTP requests by the proxy server. Red Hat has issued an important security update fixing this vulnerability in Squid 4 and libecap packages for Red Hat Enterprise Linux 8. The advisory confirms the availability of patches and recommends updating to fixed versions to mitigate the risk.

References

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