Linux Kernel: Prevent TX_RING Byte Count Overflow (CVE-2026-98850)
CVE-2026-98850 Published on October 18, 2026
net/packet: prevent TX_RING byte count overflow
In the Linux kernel, the following vulnerability has been resolved:
net/packet: prevent TX_RING byte count overflow
tpacket_snd() drains every SEND_REQUEST frame in a TX ring and adds
each valid packet length to the signed int len_sum. Userspace can
recycle completed frames concurrently, so a single blocking send call
is not bounded by the ring size.
After enough successful transmissions len_sum wraps into the negative
range. In particular, 65536 65535-byte frames followed by a 65007-byte
frame produce 0xfffffdef, or -EIOCBQUEUED. sock_sendmsg_nosec() treats
that as an impossible return and triggers a BUG. On systems configured
to panic on oops, a CAP_NET_RAW holder can panic the host kernel.
Stop before the next frame would make the byte count exceed INT_MAX.
The positive short count leaves that frame pending for a later send
call.
A two-thread TPACKET_V2 reproducer triggered the BUG on an arm64 build
of Linux 7.3-rc4. With this change, the same reproducer returned the
expected positive short count without an oops.
Products Associated with CVE-2026-98850
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Affected Versions
Linux:- Version 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 and below be12b221c0301111eeb023be04add3c6ad7c21fe is affected.
- Version 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 and below 69ca64bbb528898916f309552053c32a04a36ebc is affected.
- Version 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 and below 9fd63d284e251332f4874ef9023cde472f315f86 is affected.
- Version 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 and below 2cf81fc9505b148b1b70068303ea6ea4b1212403 is affected.
- Version 2.6.31 is affected.
- Before 2.6.31 is unaffected.
- Version 6.12.113, <= 6.12.* is unaffected.
- Version 6.18.56, <= 6.18.* is unaffected.
- Version 7.2.10, <= 7.2.* is unaffected.
- Version 7.3-rc6, <= * is unaffected.