package/squid: add upstream patch for CVE-2026-50012

- CVE-2026-50012
    Due to an Improper Input Validation bug, Squid is vulnerable to a
    Heap-based Buffer Overflow attack against cache digests.

For more information, see:
  - https://github.com/squid-cache/squid/security/advisories/GHSA-5vmx-9x64-9284
  - 19fcfe9227

Signed-off-by: Thomas Perale <thomas.perale@mind.be>

package/squid/0006-CVE-2026-50012.patch

@@ -0,0 +1,33 @@
+From 19fcfe922717c8b255270c032dcde4071c003bcd Mon Sep 17 00:00:00 2001
+From: Francesco Chemolli <5175948+kinkie@users.noreply.github.com>
+Date: Sat, 30 May 2026 10:16:33 +0000
+Subject: [PATCH] Harden peerDigestSwapInMask against invalid cache digest
+ reply (#2423)
+
+A cache_digest on-the-wire size may be bigger than the
+mask_size declared in the digest itself.
+
+Ignore the digest in case this happens.
+Upstream: https://github.com/squid-cache/squid/commit/19fcfe922717c8b255270c032dcde4071c003bcd
+CVE: CVE-2026-50012
+Signed-off-by: Thomas Perale <thomas.perale@mind.be>
+---
+ src/peer_digest.cc | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/src/peer_digest.cc b/src/peer_digest.cc
+index 741090574d6..53dac203eab 100644
+--- a/src/peer_digest.cc
++++ b/src/peer_digest.cc
+@@ -622,6 +622,11 @@ peerDigestSwapInMask(void *data, char *buf, ssize_t size)
+      * NOTENOTENOTENOTENOTE: buf doesn't point to pd->cd->mask anymore!
+      * we need to do the copy ourselves!
+      */
++    Assure(size >= 0);
++    if (fetch->mask_offset + size > static_cast<ssize_t>(pd->cd->mask_size)) {
++        finishAndDeleteFetch(fetch, "peer digest mask data too large", true);
++        return -1;
++    }
+     memcpy(pd->cd->mask + fetch->mask_offset, buf, size);
+ 
+     /* NOTE! buf points to the middle of pd->cd->mask! */

package/squid/squid.mk

@@ -27,6 +27,9 @@ SQUID_IGNORE_CVES += CVE-2026-33526
 # 0005-CVE-2026-47729.patch
 SQUID_IGNORE_CVES += CVE-2026-47729
 
+# 0006-CVE-2026-50012.patch
+SQUID_IGNORE_CVES += CVE-2026-50012
+
 SQUID_DEPENDENCIES = libcap host-libcap libtool libxml2 host-pkgconf \
 	$(if $(BR2_PACKAGE_LIBNETFILTER_CONNTRACK),libnetfilter_conntrack)
 SQUID_CONF_ENV = \