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CVE-2026-46300

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.

CVSS
7.8Highscored by the publisher (CNA)
Exploited in the wild
Yes, in CISA KEV since 28 Oct 2026CISA deadline for US federal agencies: 31 Oct 2026public exploit code
EPSS
16.1%chance of exploitation in the next 30 daystop 4% of scored CVEsFIRST score of 11 Nov 2026
Fix
Fixed in < 3.9, >= 5.10.257 and <= 5.10.*, >= 5.15.208 and <= 5.15.*per the vendor; 6 more listed below
Published
23 May 2026analysed here 12 Nov 2026

Do first. Upgrade to a fixed release: < 3.9, >= 5.10.257 and <= 5.10.*, >= 5.15.208 and <= 5.15.*, >= 6.1.174 and <= 6.1.* (and 5 more below).

Summary

Triage

Attack surface
Server-side
Exploitable
At runtime
Attack vector
local
Weaknesses

The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.

Affected products

ProductAffected versions
Linux>= cef401de7be8c4e155c6746bfccf721a4fa5fab9 and < 3599e6b3cc1ada96883d496a50a210d3afbb6987>= cef401de7be8c4e155c6746bfccf721a4fa5fab9 and < 2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c>= cef401de7be8c4e155c6746bfccf721a4fa5fab9 and < 9d3e5fd19fe1063bf607219e8562fbd567b8e8d5>= cef401de7be8c4e155c6746bfccf721a4fa5fab9 and < 78bf6b6bb19541d19fbda6242e7cfe2c682763c0>= cef401de7be8c4e155c6746bfccf721a4fa5fab9 and < 760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e>= cef401de7be8c4e155c6746bfccf721a4fa5fab9 and < 3bd9e113d50034db99d7ef69fd8e5242d15e414a>= cef401de7be8c4e155c6746bfccf721a4fa5fab9 and < 3884358a9286b17f389a72b1426fc4547c23c111>= cef401de7be8c4e155c6746bfccf721a4fa5fab9 and < f84eca5817390257cef78013d0112481c503b4a33.9Vendor says fixed in: < 3.9, >= 5.10.257 and <= 5.10.*, >= 5.15.208 and <= 5.15.*, >= 6.1.174 and <= 6.1.*, >= 6.6.141 and <= 6.6.*, >= 6.12.91 and <= 6.12.*, >= 6.18.33 and <= 6.18.*, >= 7.0.10 and <= 7.0.*, >= 7.1 and <= *

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

Products named in our analysis

  • linux:linux_kernel
  • siemens:simatic_s7-1500_cpu_1518-4_pn\/dp_mfp_firmware
  • redhat:openshift_container_platform
  • redhat:enterprise_linux
  • redhat:enterprise_linux_aus
  • redhat:enterprise_linux_eus
  • redhat:enterprise_linux_tus
  • redhat:enterprise_linux_update_services_for_sap_solutions

Fix and mitigation

WAF and other mitigations

Can a WAF block it? No. The attack needs local access to the machine, so a WAF is not on its path.

Also consider: patch

Based on the attack vector (local or physical access). We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.

Remediation steps (AI-written)

Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.

Exploitation evidence

CISA KEV catalog
Listed since 28 Oct 2026.
CISA due date
31 Oct 2026, the remediation deadline for US federal agencies
CISA required action
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Public exploit code
Yes: 1 on Exploit-DB · 1 Metasploit module · 16 GitHub proofs of concept
CISA SSVC
exploitation active, automatable no, technical impact totalAssessed by CISA 14 May 2026 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.

Exploit-DB

Metasploit

GitHub proofs of concept

and 12 more repositories

Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.

Timeline

  1. 14 May 2026First public exploit or proof of concept
  2. 14 May 2026CISA SSVC assessment: exploitation activesame day later
  3. 23 May 2026Published10 days later
  4. 28 Oct 2026Added to CISA KEV (exploited in the wild)157 days (about 5 months) later
  5. 29 Oct 2026CVE record last updated1 day later
  6. 31 Oct 2026CISA remediation due date (US federal agencies)2 days later
  7. 12 Nov 2026Analysed by vulneraibility.com12 days later

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

MetricValueWhat it means
Attack vectorLocalLocal access required (shell, logged-in user).
Attack complexityLowRepeatable attack, no special conditions.
Privileges requiredLowThe attacker needs basic user privileges.
User interactionNoneNo victim action needed.
ScopeUnchangedImpact stays within the vulnerable component.
ConfidentialityHighTotal data disclosure possible.
IntegrityHighComplete modification possible.
AvailabilityHighFull outage possible.

Common questions

Is CVE-2026-46300 being exploited?

Yes. CVE-2026-46300 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.

How severe is CVE-2026-46300?

CVE-2026-46300 is rated High with a CVSS score of 7.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2026-46300?

Yes. A fix has been recorded for CVE-2026-46300. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-46300 affect?

CVE-2026-46300 affects linux:linux_kernel, siemens:simatic_s7-1500_cpu_1518-4_pn\/dp_mfp_firmware, redhat:openshift_container_platform, redhat:enterprise_linux, and 4 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

References

NVDCVE.orgCVE DetailsSource

50 references in the CVE record, grouped by the tags the record gives them.

Advisories (33)

Show 27 more

Other links (17)

Show 11 more

Where the data on this page comes from

Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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