CVE-2026-64317: Linux kernel · Out-of-bounds Read
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.1 High · fixed in b5699642640d6cff357638738c5293985cd5a53d : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:30 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in b5699642640d6cff357638738c5293985cd5a53d, b736b12108fd116c41777628f5a333791604df26, a22cb6bb54dc167047ea9e70d97dfbc2c15649e3 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 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
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Description
In the Linux kernel, the following vulnerability has been resolved: isofs: bound Rock Ridge symlink components to the SL record get_symlink_chunk() and the SL handling in parse_rock_ridge_inode_internal() walk the variable-length components of a Rock Ridge "SL" (symbolic link) record. Each component is a two-byte header (flags, len) followed by len bytes of text, so it occupies slp->len + 2 bytes. Both loops read slp->len and advance to the next component, and get_symlink_chunk() additionally does memcpy(rpnt, slp->text, slp->len), but neither checks that the component lies within the SL record before dereferencing it. A crafted SL record whose component declares a len that runs past the record (rr->len) therefore triggers an out-of-bounds read of up to 255 bytes. When the record sits at the tail of its backing buffer - for example a small kmalloc()ed continuation block reached through a CE record - the read crosses the allocation; get_symlink_chunk() then copies the out-of-bounds bytes into the symlink body returned to user space by readlink(), disclosing adjacent kernel memory. ISO 9660 images are routinely mounted from untrusted removable media - desktop environments auto-mount them (e.g. via udisks2) without CAP_SYS_ADMIN - so the record contents are attacker-controlled. Reject any component that does not fit in the remaining record bytes before using it. In get_symlink_chunk() return NULL, like the existing output-buffer (plimit) checks, so a malformed record makes readlink() fail with -EIO rather than silently returning a truncated target; in parse_rock_ridge_inode_internal() stop the inode-size walk.
References
- git.kernel.org/stable/c/1015e1c4b2fadd9c09704e24738e46598778c869 (opens in a new tab)
- git.kernel.org/stable/c/36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee (opens in a new tab)
- git.kernel.org/stable/c/a22cb6bb54dc167047ea9e70d97dfbc2c15649e3 (opens in a new tab)
- git.kernel.org/stable/c/b736b12108fd116c41777628f5a333791604df26 (opens in a new tab)
- git.kernel.org/stable/c/6bf41db09ef935d76fcc84ccf213b42c18de95ee (opens in a new tab)
- git.kernel.org/stable/c/b5699642640d6cff357638738c5293985cd5a53d (opens in a new tab)
- git.kernel.org/stable/c/9830725078c8483c6831ec10222ae724806ea36b (opens in a new tab)
- git.kernel.org/stable/c/5fa1d6a5ec2356d2107dead614437c66fa7138b1 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)