Local privilege escalation via partial packet COW
Published Jun 16, 2026 · Updated Jun 16, 2026
Out-of-bounds writes in Linux Kernel traffic-control pedit allow local users to corrupt page-cache data through crafted edit keys. In tcf_pedit_act(), a single skb_ensure_writable() range based on tcfp_off_max_hint omits runtime header offsets, leaving part of each typed-key write outside copy-on-write protection. Exploitation requires CAP_NET_ADMIN in a network namespace, which unprivileged user namespaces can grant, and a public exploit uses the resulting page-cache overwrite to obtain root access.
Summary
What happened
Out-of-bounds writes in Linux Kernel traffic-control pedit allow local users to corrupt page-cache data through crafted edit keys. In tcf_pedit_act(), a single skb_ensure_writable() range based on tcfp_off_max_hint omits runtime header offsets, leaving part of each typed-key write outside copy-on-write protection. Exploitation requires CAP_NET_ADMIN in a network namespace, which unprivileged user namespaces can grant, and a public exploit uses the resulting page-cache overwrite to obtain root access.
The record
- CVE
- CVE-2026-46331
- Published
- Jun 16, 2026
- Updated
- Jun 16, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-787, CWE-190, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 16, 2026CVE publishedPublication date reported by the CVE source.
- Jun 16, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2ec2dd7d51a9320151f275ddbb2b53260fb32ca1
- Affected versionversion=4.19.244 <4.20
- Affected versionversion=5.10.117 <5.11
- Affected versionversion=5.15.41 <5.16
- Affected versionversion=5.17.9 <5.18
- Affected versionversion=5.18
- Affected versionversion=5.4.195 <5.5
- Affected versionversion=8b796475fd7882663a870456466a4fb315cc1bd6 <899ee91156e57784090c5565e4f31bd7dbffbc5a
- Affected versionversion=abe35bf3be51482593076d516a680d79e5fbc8e1
- Affected versionversion=b773640d5bb9e2acfd91e2695717af04d47aa116
- Affected versionversion=c19cc520b3d69904e9518d401ad0df7f4702aca0
- Affected versionversion=d0c38a914b0c4c21d553da801003d36979016726
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- PACKET_EDIT_MEMEweaponized · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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