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  4. CVE 2026 46300 net skbuff preserve shared frag marker during
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Copyright ยฉ 2026 HOL DAO LLC. All rights reserved.

Back to active CVEs
High ยท CVSS 7.8Known ExploitedCVE-2026-46300

net: skbuff: preserve shared-frag marker during coalescingCVE-2026-46300

Answer in brief

CVE-2026-46300 records a High severity (CVSS 7.8) vulnerability in net: skbuff: preserve shared-frag marker during coalescing. The current sources mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published May 23, 2026Updated Oct 31, 2026Source checked Nov 5, 2026First seen by HOL Jul 1, 2026Material review Oct 31, 2026
Upstream Advisory

Key facts

Risk
High ยท CVSS 7.8
Exploitation
Known exploited
Affected software
37 mapped packages or products
Fix availability
Available

Why this deserves its current priority

CVSS is 7.8. Known-exploitation status makes exposure review time-sensitive. 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.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:a:redhat:openshift_container_platform:*:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:siemens:simatic_s7-1500_cpu_1518-4_pn\/dp_mfp:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_aus:8.4:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_aus:8.6:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_eus:10.0:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_eus:9.4:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_eus:9.6:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_tus:8.6:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_tus:8.8:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:8.6:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:8.8:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:9.0:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:9.2:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:9.4:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:siemens:simatic_s7-1500_cpu_1518-4_pn\/dp_mfp_firmware:*:*:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Linux/Linuxgeneric>=cef401de7be8c4e155c6746bfccf721a4fa5fab9 <3599e6b3cc1ada96883d496a50a210d3afbb6987 || >=cef401de7be8c4e155c6746bfccf721a4fa5fab9 <2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c || >=cef401de7be8c4e155c6746bfccf721a4fa5fab9 <9d3e5fd19fe1063bf607219e8562fbd567b8e8d5 || >=cef401de7be8c4e155c6746bfccf721a4fa5fab9 <78bf6b6bb19541d19fbda6242e7cfe2c682763c0 || >=cef401de7be8c4e155c6746bfccf721a4fa5fab9 <760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e || >=cef401de7be8c4e155c6746bfccf721a4fa5fab9 <3bd9e113d50034db99d7ef69fd8e5242d15e414a || >=cef401de7be8c4e155c6746bfccf721a4fa5fab9 <3884358a9286b17f389a72b1426fc4547c23c111 || >=cef401de7be8c4e155c6746bfccf721a4fa5fab9 <f84eca5817390257cef78013d0112481c503b4a33599e6b3cc1ada96883d496a50a210d3afbb6987, 2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c, 9d3e5fd19fe1063bf607219e8562fbd567b8e8d5, 78bf6b6bb19541d19fbda6242e7cfe2c682763c0, 760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e, 3bd9e113d50034db99d7ef69fd8e5242d15e414a, 3884358a9286b17f389a72b1426fc4547c23c111, f84eca5817390257cef78013d0112481c503b4a3
Linux/Linuxgeneric3.9Not reported
Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric>=V3.1.6 <**
Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric>=V3.1.5 <**
Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric>=V3.1.6 <V3.1.7V3.1.7
Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric>=V3.1.6 <**
Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric>=V3.1.5 <**
Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric>=V3.1.6 <V3.1.7V3.1.7
Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric>=V3.1.6 <**
Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric>=V3.1.5 <**
Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric>=V3.1.6 <V3.1.7V3.1.7

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux, Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP.
  2. 2Review the reported fix. Update Linux/Linux to 3599e6b3cc1ada96883d496a50a210d3afbb6987; Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP to *; Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP to *; Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP to V3.1.7; Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP to *; Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP to *; Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP to V3.1.7; Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFP to *; Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFP to *; Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFP to V3.1.7 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    May 23, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 31, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Jul 1, 2026

  4. Added to CISA KEV

    Oct 28, 2026

    Evidence: source:kev:kev:kev:record

Sources and claim methodology

  • Source referenceaccess.redhat.com
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  • Source referencebugzilla.redhat.com
  • Source referencecert-portal.siemens.com
  • Source referencecert-portal.siemens.com
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
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  • Source referencegit.kernel.org
  • Source referencesecurity.access.redhat.com
  • CISA Known Exploited Vulnerabilities catalogcisa.gov
  • Source referenceopenwall.com
  • Source referenceopenwall.com
  • Source referenceopenwall.com
  • Source referenceopenwall.com
Upstream source description

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: preserve shared-frag marker during coalescing skb_try_coalesce() can attach paged frags from @from to @to. If @from has SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same externally-owned or page-cache-backed frags, but the shared-frag marker is currently lost. That breaks the invariant relied on by later in-place writers. In particular, ESP input checks skb_has_shared_frag() before deciding whether an uncloned nonlinear skb can skip skb_cow_data(). If TCP receive coalescing has moved shared frags into an unmarked skb, ESP can see skb_has_shared_frag() as false and decrypt in place over page-cache backed frags. Propagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged frags. The tailroom copy path does not need the marker because it copies bytes into @to's linear data rather than transferring frag descriptors.

Quoted source text, attributed separately from HOL analysis.

Record context

Vulnerability class
Memory Corruption
EPSS
Not reported
CWE IDs
CWE-787, CWE-123, CWE-456
Source
CVE List V5
Source checked
Nov 5, 2026
References
51 linked sources
Open source record