VulnerabilityPublished 24 Jun 2026Updated 6 Nov 2026

CVE-2026-53014: Linux kernel · net/sched: act_mirred: fix wrong device for mac_header_xmit check in tcf_blockcast_redir

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in 4764953c4b47585eb72797b216b63a831dc0c7e6 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:49 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in 4764953c4b47585eb72797b216b63a831dc0c7e6, 4510d140524ca7d6e772db962e013f26f09a63b1, 8fda5174286119addd28473fb2ec5bdf521c05a8 +1

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to 4764953c4b47585eb72797b216b63a831dc0c7e6, 4510d140524ca7d6e772db962e013f26f09a63b1, 8fda5174286119addd28473fb2ec5bdf521c05a8 or 7db3e4e03032261b1b519341123fc30d995478ca.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 42f39036cda808d3de243192a2cf5125f12f3047, < 4764953c4b47585eb72797b216b63a831dc0c7e6	Fixed in 4764953c4b47585eb72797b216b63a831dc0c7e6
LinuxLinux	Affected ≥ 42f39036cda808d3de243192a2cf5125f12f3047, < 4510d140524ca7d6e772db962e013f26f09a63b1	Fixed in 4510d140524ca7d6e772db962e013f26f09a63b1
LinuxLinux	Affected ≥ 42f39036cda808d3de243192a2cf5125f12f3047, < 8fda5174286119addd28473fb2ec5bdf521c05a8	Fixed in 8fda5174286119addd28473fb2ec5bdf521c05a8
LinuxLinux	Affected ≥ 42f39036cda808d3de243192a2cf5125f12f3047, < 7db3e4e03032261b1b519341123fc30d995478ca	Fixed in 7db3e4e03032261b1b519341123fc30d995478ca
LinuxLinux	Affected =6.8	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_mirred: fix wrong device for mac_header_xmit check in tcf_blockcast_redir In tcf_blockcast_redir(), when iterating block ports to redirect packets to multiple devices, the mac_header_xmit flag is queried from the wrong device. The loop sends to dev_prev but queries dev_is_mac_header_xmit(dev) — which is the NEXT device in the iteration, not the one being sent to. This causes tcf_mirred_to_dev() to make incorrect decisions about whether to push or pull the MAC header. When the block contains mixed device types (e.g., an ethernet veth and a tunnel device), intermediate devices get the wrong mac_header_xmit flag, leading to skb header corruption. In the worst case, skb_push_rcsum with an incorrect mac_len can exhaust headroom and panic. The last device in the loop is handled correctly (line 365-366 uses dev_is_mac_header_xmit(dev_prev)), confirming this is a copy-paste oversight for the intermediate devices. Fix by using dev_prev instead of dev for the mac_header_xmit query, consistent with the device actually being sent to.

References

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