CVE-2026-98049
In the Linux kernel, the following vulnerability has been resolved: bpf: zero extend the result of…
- Risk score
- 43/100
- CVSS
- 5.5 v3.1
- Exploit chance (30 days)
- 0.1%
- Published
- 25 Sep 2026
Open in the live forecast Today's forecast
What to know
- What it is
- In the Linux kernel, the following vulnerability has been resolved: bpf: zero extend the result of an arena 32-bit cmpxchg bpf_convert_ctx_accesses() rewrites an atomic on an arena pointer from BPF_STX | BPF_ATOMIC to BPF_STX | BPF_PROBE_ATOMIC, and it runs before bpf_opt_subreg_zext_lo32_rnd_hi32(). That pass emits a…
- Affected
- Linux kernel
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Story map
At a glance
Linux kernel: Amber, patch this week. In the Linux kernel, the following vulnerability has been resolved: sctp: fix a TOCTOU race in SCTP_CMD_TIMER_START The SCTP_CMD_TIMER_START handler checks timer_pending() before calling timer_reduce(). The timer can expire and detach between these operations, causing timer_reduce() to rearm the timer without taking t…
The flaws
- CVE-2026-98049: In the Linux kernel, the following vulnerability has been resolved: bpf: zero extend the result of… (CVSS 5.5 · EPSS 0%)
- CVE-2026-98130: Race condition (CVSS 8.1 · EPSS 0%)
- CVE-2026-98115: Race condition (CVSS 8.8 · EPSS 0%)
- CVE-2026-98052: In the Linux kernel, the following vulnerability has been resolved: net: bcmasp: clear txcb->last… (CVSS 7.8 · EPSS 0%)
The fix
Fix: Apply the vendor's security update; see the linked advisory.
Who is exposed: Linux kernel
Where it stands
- No known exploitation
Connects to
- Same weakness: CWE-681 (CWE-681). 12 other warnings in 30 days
- Same product: Earlier Linux kernel warnings. 61 in the last 90 days
Why it is Yellow
- CVSS 5.5 medium
- On your watchlist: linux kernel
References
Original description
In the Linux kernel, the following vulnerability has been resolved: bpf: zero extend the result of an arena 32-bit cmpxchg bpf_convert_ctx_accesses() rewrites an atomic on an arena pointer from BPF_STX | BPF_ATOMIC to BPF_STX | BPF_PROBE_ATOMIC, and it runs before bpf_opt_subreg_zext_lo32_rnd_hi32(). That pass emits an explicit zero extension for a 32-bit cmpxchg even when bpf_jit_needs_zext() is false. This is done because on some architectures 32-bit cmpxchg requires explicit zero extension for the dst register. E.g. on x86-64 'lock cmpxchg' does not change the %eax if comparison is successful, while BPF semantics declare that each operation on a 32-bit register zero extends it's upper half. is_cmpxchg_insn() matches BPF_MODE == BPF_ATOMIC only, so an arena cmpxchg misses said zero extension adjustment. This patch adjusts is_cmpxchg_insn() to match BPF_PROBE_ATOMIC alongside BPF_ATOMIC.
Last activity 25 Sep 2026. Patch Forecast updates every hour.