---
id: CVE-2026-50012
title: Squid is a caching proxy for the Web
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'…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:H'
cwe:
  - CWE-20
  - CWE-122
vendor: squid-cache
product: squid
affected:
  - squid < 7.6
patched:
  - squid 7.6
published: '2026-07-16'
updated: '2026-07-20'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-50012'
references:
  - url: >-
      https://github.com/squid-cache/squid/commit/19fcfe922717c8b255270c032dcde4071c003bcd
    label: security-advisories@github.com
  - url: 'https://github.com/squid-cache/squid/pull/2423'
    label: security-advisories@github.com
  - url: 'https://github.com/squid-cache/squid/releases/tag/SQUID_7_6'
    label: security-advisories@github.com
  - url: >-
      https://github.com/squid-cache/squid/security/advisories/GHSA-5vmx-9x64-9284
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.02681
epssPercentile: 0.85215
ingestedAt: '2026-07-20T02:36:03.264Z'
---

## Overview

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.

## Affected

- `squid < 7.6`

## Remediation

Upgrade past the affected range:

- `squid 7.6`