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CVE-2026-98850

Linux: net/packet: prevent TX_RING byte count overflow

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
NoneNot scored
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.16%Chance of exploitation activity in the next 30 days, higher than 4% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in69ca64bbb528898916f309552053c32a04a36ebcAlso 9fd63d284e251332f4874ef9023cde472f315f86, 2cf81fc9505b148b1b70068303ea6ea4b1212403CVE List
Published18 Oct 2026Updated 21 Oct 2026CVE List

What fixes it

  • 69ca64bbb528898916f309552053c32a04a36ebcLinuxCVE List
  • 9fd63d284e251332f4874ef9023cde472f315f86LinuxCVE List
  • 2cf81fc9505b148b1b70068303ea6ea4b1212403LinuxCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

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.

Text from CVE List

Affected versions 12

  • Linuxaffected: 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 before ae169d318d5d23bac76ece90a7e2b5cb760ed043CVE List
  • Linuxaffected: 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 before be12b221c0301111eeb023be04add3c6ad7c21feCVE List
  • Linuxaffected: 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 before 69ca64bbb528898916f309552053c32a04a36ebcCVE List
  • Linuxaffected: 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 before 9fd63d284e251332f4874ef9023cde472f315f86CVE List
  • Linuxaffected: 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 before 2cf81fc9505b148b1b70068303ea6ea4b1212403CVE List
  • Linuxaffected: 2.6.31CVE List
  • Linuxunaffected: all versions before 2.6.31CVE List
  • Linuxunaffected: 6.6.160 through 6.6.*CVE List
  • Linuxunaffected: 6.12.113 through 6.12.*CVE List
  • Linuxunaffected: 6.18.56 through 6.18.*CVE List
  • Linuxunaffected: 7.2.10 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 5