Answer in brief
CVE-2026-72251 records a Unknown severity vulnerability in netfilter: nf_nat_sip: reload possible stale data pointer. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-72251 records a Unknown severity vulnerability in netfilter: nf_nat_sip: reload possible stale data pointer. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=7266507d89991fa1e989283e4e032c6d9357fe26 <bded21a4bf9bf86a79148be735723a97ca9a7532 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <dc11f26685aa850f237226f0f463647aea58ab7c || >=7266507d89991fa1e989283e4e032c6d9357fe26 <e38143c9b477f2968024c47c647dd4456a40aff1 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <57e4e29644ec054d7021d296407e7ddd844afea2 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <2bcf2c5052fb5e73e255140ab43f056aef409c27 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68 | bded21a4bf9bf86a79148be735723a97ca9a7532, dc11f26685aa850f237226f0f463647aea58ab7c, e38143c9b477f2968024c47c647dd4456a40aff1, 57e4e29644ec054d7021d296407e7ddd844afea2, eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17, 2bcf2c5052fb5e73e255140ab43f056aef409c27, 0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7, 77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68 |
| Linux/Linuxgeneric | 3.9 | Not reported |
Published upstream
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 15, 2026
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.
Quoted source text, attributed separately from HOL analysis.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=7266507d89991fa1e989283e4e032c6d9357fe26 <bded21a4bf9bf86a79148be735723a97ca9a7532 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <dc11f26685aa850f237226f0f463647aea58ab7c || >=7266507d89991fa1e989283e4e032c6d9357fe26 <e38143c9b477f2968024c47c647dd4456a40aff1 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <57e4e29644ec054d7021d296407e7ddd844afea2 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <2bcf2c5052fb5e73e255140ab43f056aef409c27 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7 || >=7266507d89991fa1e989283e4e032c6d9357fe26 <77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68 | bded21a4bf9bf86a79148be735723a97ca9a7532, dc11f26685aa850f237226f0f463647aea58ab7c, e38143c9b477f2968024c47c647dd4456a40aff1, 57e4e29644ec054d7021d296407e7ddd844afea2, eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17, 2bcf2c5052fb5e73e255140ab43f056aef409c27, 0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7, 77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68 |
| Linux/Linuxgeneric | 3.9 | Not reported |
Published upstream
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 15, 2026
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.
Quoted source text, attributed separately from HOL analysis.