Kernel heap overflow in widely deployed Linux iscsi target can enable kernel memory corruption/RCE on systems offering iSCSI storage; impacts enterprise infrastructure.
CVE-2026-63886
Linux kernel iSCSI CHAP base64 buffer overflow causing kernel memory corruption
Is CVE-2026-63886 being exploited?
Not confirmed. CVE-2026-63886 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 0.71% probability of exploitation in the next 30 days.
How severe is CVE-2026-63886?
CVE-2026-63886 is rated Critical with a CVSS score of 9.8. 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-2026-63886?
Yes. A fix has been recorded for CVE-2026-63886. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-63886 affect?
CVE-2026-63886 affects Linux kernel (iscsi target / scsi target subsystem). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-63886?
Apply vendor kernel updates or upstream patch; restrict iSCSI access until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Heap overflow in kernel iscsi CHAP base64 decode allows kernel memory corruption, leading to remote crash, privilege escalation, or potential kernel RCE via crafted CHAP response.
Immediate action required
- affected>= 1e5733883421495908f3b90d9d807663038b4136 and < 82454e6f21e56ea9a0a9de7d0ff7e1dfb83e34d6
- affected>= 1e5733883421495908f3b90d9d807663038b4136 and < edd06675a02376ea8347dba7c29ad982ba5b36ee
- affected>= 1e5733883421495908f3b90d9d807663038b4136 and < bf154c657828ed05399bca5d98cf1611bb048b12
- affected>= 1e5733883421495908f3b90d9d807663038b4136 and < 4a3a19c98a8207ad08bec554703d90f2c34a8cc6
- affected>= 1e5733883421495908f3b90d9d807663038b4136 and < c04e85799356120209b351a148ac2db888d5ffd9
- affected>= 1e5733883421495908f3b90d9d807663038b4136 and < 85db7391310b1304d2dc8ae3b0b12105a9567147
- affected6.0
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.