Local privilege escalation via act_mirred double-free
Published Apr 3, 2024 · Updated Aug 5, 2026
Use-after-free in the Linux traffic-control mirred action allows local users to disclose or alter kernel memory or crash the system. In tcf_mirred_act(), returning TC_ACT_SHOT after tcf_mirred_forward() has transferred the skb causes the networking core to free an already released buffer. Reachability requires locally creating an ingress qdisc and act_mirred redirect with namespace CAP_NET_ADMIN, then injecting a frame that takes a drop path.
Summary
What happened
Use-after-free in the Linux traffic-control mirred action allows local users to disclose or alter kernel memory or crash the system. In tcf_mirred_act(), returning TC_ACT_SHOT after tcf_mirred_forward() has transferred the skb causes the networking core to free an already released buffer. Reachability requires locally creating an ingress qdisc and act_mirred redirect with namespace CAP_NET_ADMIN, then injecting a frame that takes a drop path.
The record
- CVE
- CVE-2024-26739
- Published
- Apr 3, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 3, 2024CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.19
- Affected versionversion=e5cf1baf92cb785b90390db1c624948e70c8b8bd <0117fe0a4615a7c8d30d6ebcbf87332fbe63e6fd
- Affected versionversion=e5cf1baf92cb785b90390db1c624948e70c8b8bd <166c2c8a6a4dc2e4ceba9e10cfe81c3e469e3210
- Affected versionversion=e5cf1baf92cb785b90390db1c624948e70c8b8bd <28cdbbd38a4413b8eff53399b3f872fd4e80db9d
- Affected versionversion=e5cf1baf92cb785b90390db1c624948e70c8b8bd <9d3ef89b6a5e9f2e940de2cef3d543be0be8dec5
- Affected versionversion=e5cf1baf92cb785b90390db1c624948e70c8b8bd <e873e8f7d03a2ee5b77fb1a305c782fed98e2754
- Affected versionversion=e5cf1baf92cb785b90390db1c624948e70c8b8bd <f4e294bbdca8ac8757db436fc82214f3882fc7e7
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.
Public exploit references
No public exploit references are available in this record.
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
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo