CVE-2026-93125: Linux kernel · bpf: Reject rdonly/rdwr_buf_size kfunc arguments that exceed u32 max
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in b6ac0b5732047d43172b9dfbe6b57b9b8de303c2 : patch Linux kernel soon.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in b6ac0b5732047d43172b9dfbe6b57b9b8de303c2, 2147065d3a4e1d5d42ae553fef165f17ec5e0e79, 93a20b14f8627b2d3486e3ec1d3f2e7275a506ec +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject rdonly/rdwr_buf_size kfunc arguments that exceed u32 max check_kfunc_args() detects a kfunc argument named rdonly_buf_size or rdwr_buf_size and stores reg->var_off.value into meta->r0_size, a u64, and does not bound it. check_kfunc_call() later copies that value into the returned register's mem_size field: meta->r0_size = reg->var_off.value; ... regs[BPF_REG_0].mem_size = meta.r0_size; regs[BPF_REG_0].mem_size is u32. A constant whose upper 32 bits are set gets truncated instead of causing a load-time rejection, so the verifier records a PTR_TO_MEM register with an approximately 4 GiB mem_size for whatever allocation the kfunc returned. A later access check against that register uses the truncated, wrong bound. Reject rdonly_buf_size/rdwr_buf_size values that exceed U32_MAX at the point meta->r0_size is set.
References
- git.kernel.org/stable/c/2147065d3a4e1d5d42ae553fef165f17ec5e0e79 (opens in a new tab)
- git.kernel.org/stable/c/b6ac0b5732047d43172b9dfbe6b57b9b8de303c2 (opens in a new tab)
- git.kernel.org/stable/c/93a20b14f8627b2d3486e3ec1d3f2e7275a506ec (opens in a new tab)
- git.kernel.org/stable/c/56a3846830ac95a472297d0cbba75cbff29540bb (opens in a new tab)
- git.kernel.org/stable/c/2aaf67f0516fde29620d0edfc29c01b9ea7ad430 (opens in a new tab)