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CVE PROGRAM SOURCE RECORD9.8 Critical

CVE-2026-72251

netfilter: nf_nat_sip: reload possible stale data pointer

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_nat_sip: reload possible stale data pointer quoting sashiko: ------------------------------------------------------------------------ [..] noticed a potential memory bug and header corruption involving the SIP NAT helper. In net/netfilter/nf_nat_sip.c:nf_nat_sip(): if (skb_ensure_writable(skb, skb->len)) { nf_ct_helper_log(skb, ct, "cannot mangle packet"); return NF_DROP; } uh = (void *)skb->data + protoff; uh->dest = ct_sip_info->forced_dport; if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff, 0, 0, NULL, 0)) { If a cloned or fragmented SKB is reallocated by skb_ensure_writable(), the old data buffer is freed. However, nf_nat_sip() fails to update *dptr to point to the new buffer. It also appears to use nf_nat_mangle_udp_packet() on what could be a TCP packet, which would overwrite the sequence number with a checksum update. ------------------------------------------------------------------------ nf_conntrack_sip linerizes skbs, hence no fragmented skb can be seen. But clones are possible, so rebuild dptr. Disable nf_nat_mangle_udp_packet() branch for TCP streams. It doesn't look like this can ever happen, else we should have received bug reports about this, so just check the conntrack is UDP and drop otherwise. The calling conntrack_sip set ->forced_dport for SIP_HDR_VIA_UDP messages, so I don't think this is ever expected to be true for a TCP stream.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 7266507d89991fa1e989283e4e032c6d9357fe26 to < bded21a4bf9bf86a79148be735723a97ca9a7532affected
  • 7266507d89991fa1e989283e4e032c6d9357fe26 to < dc11f26685aa850f237226f0f463647aea58ab7caffected
  • 7266507d89991fa1e989283e4e032c6d9357fe26 to < e38143c9b477f2968024c47c647dd4456a40aff1affected
  • 7266507d89991fa1e989283e4e032c6d9357fe26 to < 57e4e29644ec054d7021d296407e7ddd844afea2affected
  • 7266507d89991fa1e989283e4e032c6d9357fe26 to < eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17affected
  • 7266507d89991fa1e989283e4e032c6d9357fe26 to < 2bcf2c5052fb5e73e255140ab43f056aef409c27affected
  • 7266507d89991fa1e989283e4e032c6d9357fe26 to < 0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7affected
  • 7266507d89991fa1e989283e4e032c6d9357fe26 to < 77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68affected

Linux Linux

Default version status: affected

  • 3.9affected
  • 0 to < 3.9unaffected
  • 5.10.261 to ≤ 5.10.*unaffected
  • 5.15.212 to ≤ 5.15.*unaffected
  • 6.1.178 to ≤ 6.1.*unaffected
  • 6.6.145 to ≤ 6.6.*unaffected
  • 6.12.97 to ≤ 6.12.*unaffected
  • 6.18.40 to ≤ 6.18.*unaffected
  • 7.1.5 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References