Use-after-free in Linux kernel AF_UNIX MSG_OOB handling
CVE-2025-38236 is a use-after-free vulnerability in the Linux kernel AF_UNIX implementation, specifically in stream UNIX domain socket out-of-band (MSG_OOB) handling. The bug is triggered in unix_stream_read_generic() when consecutive consumed OOB skbs are left on the receive queue. In the reported sequence, multiple MSG_OOB sends and receives cause the receive queue to contain two leading consumed OOB skbs followed by a real OOB skb. During a subsequent recv() without MSG_OOB, unix_stream_read_generic() peeks a consumed OOB skb, manage_oob() advances to the next consumed OOB skb, and then SO_PEEK_OFF-related logic advances again because it does not expect unix_skb_len(skb) to be 0 for consumed OOB skbs. This causes the code to fetch, read, and free the not-yet-consumed OOB skb incorrectly. A later recv(MSG_OOB) then accesses the freed skb, resulting in a KASAN-reported slab use-after-free in unix_stream_read_actor(). The fix described in the content avoids leaving consecutive consumed OOB skbs by freeing a consumed previous skb while receiving an OOB skb in unix_stream_recv_urg().
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Recent activity
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High-severity kernel elevation-of-privilege issue in Net/EPoll subsystems referenced as part of the December 2025 Android bulletin’s kernel bug set.
High-severity Android kernel vulnerability referenced in the December 2025 bulletin as expanding the local kernel privilege-escalation attack surface.
Linux kernel use-after-free bug in stream-oriented UNIX domain sockets’ MSG_OOB handling (Linux >= 6.9), discussed in the context of exploitation from the Chrome renderer sandbox.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.