Core OS kernel component widely deployed; SMB client vulnerability could expose kernel memory across Linux systems.
CVE-2026-31708
Linux SMB client OOB read may disclose kernel heap via SMB2 QUERY_INFO.
Is CVE-2026-31708 being exploited?
Not confirmed. CVE-2026-31708 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.31% probability of exploitation in the next 30 days.
How severe is CVE-2026-31708?
CVE-2026-31708 is rated High with a CVSS score of 8.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-31708?
Yes. A fix has been recorded for CVE-2026-31708. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-31708 affect?
CVE-2026-31708 affects Linux kernel SMB client (smb2). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-31708?
Apply latest kernel update; reboot if required
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attackers can trigger an OOB read to reveal adjacent kernel memory via SMB2 QUERY_INFO, leading to information disclosure.
Patch when possible
- affected>= f5778c398713692a16150ae96e5c8270bab8399f and < e66bdc0704977ecee667a81d38255b579c2353d0
- affected>= f5778c398713692a16150ae96e5c8270bab8399f and < 9e203dbb5402897c43130fb171a2617008a91f45
- affected>= f5778c398713692a16150ae96e5c8270bab8399f and < 1dd757379997b71a328a4b591ffaf481acd0ead1
- affected>= f5778c398713692a16150ae96e5c8270bab8399f and < a34d456934fe42e4da5d2cc07787bf418bee99c6
- affected>= f5778c398713692a16150ae96e5c8270bab8399f and < ac2f14e4705d020f04e806efa0d49ab8dc2b145f
- affected>= f5778c398713692a16150ae96e5c8270bab8399f and < 078fae8f50adebb903ccf2252b44391324571e78
- affected>= f5778c398713692a16150ae96e5c8270bab8399f and < 85fd46ee26a11841c670449508025965f61ce131
- affected>= f5778c398713692a16150ae96e5c8270bab8399f and < a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e
- affected5.1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.