Medium [CVE-2026-50012] memory corruption in cache_digest reply handling
This medium-severity Red Hat Linux advisory covers CVE-2026-50012 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Summary
Squid is a caching proxy for the Web.
Prior to 7.6, due to an improper input validation bug in cache digest reply handling (peerDigestSwapInMask in src/peer_digest.cc), Squid is vulnerable to a heap-based buffer overflow: a cache digest's on-the-wire size may be larger than the mask_size declared within the digest, so a trusted peer sending a maliciously crafted reply to a cache_digest request message can trigger the overflow.
This attack is limited to Squid instances compiled with the --enable-cache-digests option and configured with cache_peer entries. This issue is fixed in version 7.6.
A flaw was found in Squid. This issue allows a trusted server to cause a denial of service when sending specially crafted replies to cache_digest request messages.
To exploit this issue, an attacker must control a trusted cache peer server. Also, cache digests are not enabled in the default configuration.
Squid deployments that do not use cache peering are not affected. Furthermore, even those that do are only vulnerable when the attacker controls a configured peer server within the same administrative domain.
A compromised peer can reliably crash the Squid process via a heap-based buffer overflow during digest exchange, but code execution faces considerable practical security barriers.
Is CVE-2026-50012 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-50012 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-50012?
The advisory VulniPulse tracks names no fixed release. Follow Red Hat's guidance for workarounds and updates.
Confirm against the vendor advisory before you patch.
- < 7.6
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
Mitigation checklist
- To mitigate this vulnerability, restrict or disable cache digest processing for cache peers by adding the appropriate settings to the squid.conf configuration file: Disable cache digests for any cache_peer not under direct control by adding the no-digest option. This completely removes the vulnerability for those peers at the cost of increased bandwidth. Use of HTCP or ICP as alternative protocols can reduce that cost. ~~~ # Example of disabling digests for an untrusted peer. cache_peer untrusted.server.example.com parent 3128 3130 no-digest ~~~ Audit the Squid configuration and ensure that all configured cache_peer entries are under direct control and are trusted. Restricting cache peering exclusively to trusted domains greatly reduces the risk of exploitation. ~~~ # Example of a fully trusted peer without the no-digest flag. cache_peer trusted.internal.example.com parent 3128 3130 ~~~
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
Get an email when Red Hat RHEL & SELinux publishes the next one.
See Red Hat RHEL & SELinux's last 90 days of advisories first. Then choose one product with live alerts free for life, or a free month of real-time alerts on everything with the severity, the fixed version and the vendor's link (card needed, then US$15/month; we email you before the first charge).
More Red Hat Linux advisories
- CVE-2026-111497Oct 22, 2026Out-of-Bounds Write in Google Brotli Decoder
- CVE-2026-109619Oct 21, 2026fatal error handling retains stale request state leading to use-after-free
- CVE-2026-109618Oct 21, 2026OOM bailout during request parsing leads to memory corruption and RCE
- CVE-2026-119977Oct 31, 2026Arbitrary code execution via predictable upgrade staging paths
- CVE-2026-97229Oct 13, 2026integer overflow issue in CI/CD regular expression compiler
- CVE-2026-64849Aug 17, 2026Unauthenticated full-read SSRF in webhook delivery: _validate_webhook_url bypassed
iPhone and Android apps · New on the App Store
Monitor future Red Hat Linux CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 34 official vendor sources and 160+ reviewed platform categories.
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.