CVE-2026-53390
Authenticated SMB client can trigger kernel heap out-of-bounds read in ksmbd ACL parsing.
Is CVE-2026-53390 being exploited?
Not confirmed. CVE-2026-53390 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 0.47% probability of exploitation in the next 30 days.
How severe is CVE-2026-53390?
CVE-2026-53390 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-2026-53390?
Yes. A fix has been recorded for CVE-2026-53390. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-53390 affect?
CVE-2026-53390 affects Linux kernel (ksmbd SMB server). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-53390?
Apply updated Linux kernel/ksmbd security patches promptly
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated SMB client can cause a kernel heap OOB read via crafted DACL, enabling information leak, kernel crash, or facilitating privilege escalation.
Patch when possible
- affected>= 282cbbb476b9f35793452bc461934af4c7eca169 and < c7488c85fd822959e9b5c22fbd9e7c8a21caf5e0
- affected>= f20adc4ef7428bc485ee83fd1a592252fb87718b and < 988c93d3bba066d8669143e6ec30bb2be9608d53
- affected>= 325d4ac11f526cb8964cff14548ccf02d8c756d8 and < 36599894fa8536fefdf1e296c0af71b8b7226859
- affected>= 95e5aa3c3261da8c95b27d7aecf8ee39b9f86a4c and < d5c81a095c86fe507c032d08f3a8cfc518444927
- affected>= 90089584b2e25c4510b7b987387b4405f0673ece and < 7627ff8c4f9919f14de562b0160ab4ec9d80b1f7
- affected>= d07b26f39246a82399661936dd0c853983cfade7 and < e36e35660adb9b8ef1435ac359151dda5f094c55
- affected>= d07b26f39246a82399661936dd0c853983cfade7 and < 1ef06004ed4bd6d3ed8c840d9d1a376b66d4935b
- affected151b1799861fde38087c08f613abc2843ef597b0
- affected>= 5.15.210 and < 5.15.212
- affected>= 6.1.176 and < 6.1.177
- affected>= 6.6.140 and < 6.6.144
- affected>= 6.12.84 and < 6.12.95
- affected>= 6.18.25 and < 6.18.38
- affected>= 7.0.2 and < 7.1
- affected7.1
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.