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CVE-2026-98573
net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6()
Published 2026-10-18 (today) by the Linux kernel CNA. Subsystem net/core. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-98573 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixed | 6.1.190-1 | Update the kernel and reboot. Fixed in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.113-1 | Update the kernel and reboot. Fixed in 6.12.113-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.9-1 | Update the kernel and reboot. Fixed in 7.2.9-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.9-1 | Update the kernel and reboot. Fixed in 7.2.9-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
skb_maybe_pull_tail() subtracts skb_headlen(skb) from the unsigned max argument and passes the result to __pskb_pull_tail() as a signed int. The function does not ensure that max is at least skb_headlen(skb). This can happen while parsing IPv6 extension headers when an skb already has a linear area larger than MAX_IPV6_HDR_LEN. Once the parser needs data beyond the linear area, max - skb_headlen(skb) wraps and is converted to a negative delta. __pskb_pull_tail() then passes that negative length to skb_copy_bits(), where it can become a very large copy length. Pass the requested length itself as the pull bound at the three extension-header call sites, so the delta can no longer go negative.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
net/core/skbuff.c
- What this is
- NETWORKING [GENERAL]MAINTAINERS section matched on net/ · netdev@vger.kernel.org · Maintained
Show whether Debian builds this, per release
Debian builds this code. Every release below compiles the affected file into the kernels it ships.
- bookworm, trixie, forky, sidy
- y
- built into the kernel image on every flavour - only a patch removes it
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS Debian linux-config packages
Signals
- Published
- 2026-10-18 (today)source
- CVSS
- no vector published, unrated
- Attack vector
- not published
- EPSS
- not scored
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/core
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 3.13 | 5.10.271 | 9c4e432132a9 |
| 3.13 | 5.15.222 | 718747afa546 |
| 3.13 | 6.1.189 | a0ad0473c09d |
| 3.13 | 6.6.158 | b2da5ed3d8c7 |
| 3.13 | 6.12.112 | 6c28c31f051d |
| 3.13 | 6.18.55 | cfa643f2ca36 |
| 3.13 | 7.2.9 | d7f474226809 |
| 3.13 | 7.3 | 3b4e0b0c008a |
Why the CNA scored it this way
The kernel CNA published no CVSS vector and no reasoning for CVE-2026-98573, which is why it is shown as unrated rather than given an invented score. 6,405 of the 20,413 CVEs here carry reasoning; this is not one of them.