# CVE-2026-53002: netfilter: conntrack: remove sprintf usage

Status: published. Published: 2026-06-24. Updated: 2026-11-10.

In the Linux kernel, the following vulnerability has been resolved:

netfilter: conntrack: remove sprintf usage

Replace it with scnprintf, the buffer sizes are expected to be large enough
to hold the result, no need for snprintf+overflow check.

Increase buffer size in mangle_content_len() while at it.

BUG: KASAN: stack-out-of-bounds in vsnprintf+0xea5/0x1270
Write of size 1 at addr [..]
 vsnprintf+0xea5/0x1270
 sprintf+0xb1/0xe0
 mangle_content_len+0x1ac/0x280
 nf_nat_sdp_session+0x1cc/0x240
 process_sdp+0x8f8/0xb80
 process_invite_request+0x108/0x2b0
 process_sip_msg+0x5da/0xf50
 sip_help_tcp+0x45e/0x780
 nf_confirm+0x34d/0x990
 [..]

## Remediation

- fix: RHSA-2026:66180: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9)

RHSA-2026:66000: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8)

RHSA-2026:64770: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) (source: ADP: redhat-SADP)
- workaround: To mitigate this issue, prevent the nf_conntrack_sip and nf_nat_sip modules from being loaded. See https://access.redhat.com/solutions/41278 for instructions. (source: ADP: redhat-SADP)

## Affected products and versions

- Linux / Linux: ≥ 9fafcd7b203229c3f3893a475741afc27e276306; < 2f793ba78470a99f40389b7dc60a81d9f5ad3956 (affected, git); ≥ 9fafcd7b203229c3f3893a475741afc27e276306; < 6bbf829b4c1b44c941c47dd0d710f1393258f3d5 (affected, git); ≥ 9fafcd7b203229c3f3893a475741afc27e276306; < ab64e61c9323fa6de21bd20da1ddb29a0fb65d34 (affected, git); ≥ 9fafcd7b203229c3f3893a475741afc27e276306; < 1c9fb8aeed06790d42cdcd00f6c3ce0b9e926c1e (affected, git); ≥ 9fafcd7b203229c3f3893a475741afc27e276306; < a8e0a32a23d3f34862af3b4da792ecb3a891a9a3 (affected, git); ≥ 9fafcd7b203229c3f3893a475741afc27e276306; < 8e3be0d12615a173fe260cd42753ca7a001acbf2 (affected, git); ≥ 9fafcd7b203229c3f3893a475741afc27e276306; < c08ff52e44945e6ef4ce0790f49ea761b060c45b (affected, git); ≥ 9fafcd7b203229c3f3893a475741afc27e276306; < 6e7066bdb481a87fe88c4fa563e348c03b2d373d (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.20 (affected); ≥ 0; < 2.6.20 (unaffected, semver); ≥ 5.10.258; ≤ 5.10.* (unaffected, semver); ≥ 5.15.209; ≤ 5.15.* (unaffected, semver); ≥ 6.1.175; ≤ 6.1.* (unaffected, semver); ≥ 6.6.141; ≤ 6.6.* (unaffected, semver); ≥ 6.12.91; ≤ 6.12.* (unaffected, semver); ≥ 6.18.33; ≤ 6.18.* (unaffected, semver); ≥ 7.0.10; ≤ 7.0.* (unaffected, semver); ≥ 7.1; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux
- Red Hat / Red Hat Enterprise Linux 8 (kernel-rt): ≥ 0:4.18.0-553.160.1.rt7.501.el8_10; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8 (kernel): ≥ 0:4.18.0-553.160.1.el8_10; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9 (kernel): ≥ 0:5.14.0-687.46.1.el9_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 10 (kernel): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 6 (kernel): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 7 (kernel): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 7 (kernel-rt): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9 (kernel-rt): Version range not reported. Source: ADP: redhat-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CVSS 3.1: 9.8 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H; source: CNA: Linux

- CVSS 3.1: 7 (high); CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H; source: ADP: redhat-SADP

- CISA KEV: No listing in collected sources

- EPSS: 0.37% as of 2026-11-09; percentile 30.90%

- SSVC: exploitation none; automatable yes; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-787

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/2f793ba78470a99f40389b7dc60a81d9f5ad3956 (CNA: Linux)

- https://git.kernel.org/stable/c/6bbf829b4c1b44c941c47dd0d710f1393258f3d5 (CNA: Linux)

- https://git.kernel.org/stable/c/ab64e61c9323fa6de21bd20da1ddb29a0fb65d34 (CNA: Linux)

- https://git.kernel.org/stable/c/1c9fb8aeed06790d42cdcd00f6c3ce0b9e926c1e (CNA: Linux)

- https://git.kernel.org/stable/c/a8e0a32a23d3f34862af3b4da792ecb3a891a9a3 (CNA: Linux)

- https://git.kernel.org/stable/c/8e3be0d12615a173fe260cd42753ca7a001acbf2 (CNA: Linux)

- https://git.kernel.org/stable/c/c08ff52e44945e6ef4ce0790f49ea761b060c45b (CNA: Linux)

- https://git.kernel.org/stable/c/6e7066bdb481a87fe88c4fa563e348c03b2d373d (CNA: Linux)

- https://access.redhat.com/security/cve/CVE-2026-53002 (ADP: redhat-SADP; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2492329 (ADP: redhat-SADP; issue-tracking, x_refsource_REDHAT)

- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53002.json (ADP: redhat-SADP; x_sadp-csaf-vex)

- https://access.redhat.com/errata/RHSA-2026:66180 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:66000 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:64770 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (ADP: siemens-SADP)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-53002; retrieved 2026-11-10; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-53002; retrieved 2026-11-10; source updated Not reported

Revision: 87bfef949e6bf393eaf4b4d973f383114c97a1aad372da6e22fbc858be6b2f79

Canonical: https://y2.dev/cve/CVE-2026-53002

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