Vulnerability in Linux kernel (CVE-2026-93259)
Summary
Vulnerability in Linux kernel (CVE-2026-93259). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
powerpc/irq: Fix missing r2 clobber in PCREL inline assembly
In CONFIG_PPC_KERNEL_PCREL mode, r2 is no longer reserved for the TOC
pointer and is available as a caller-saved register [0].
Both call_do_irq() and call_do_softirq() use inline assembly to call
functions with stack switching, but fail to list r2 in their clobber
lists. This causes the compiler to assume r2 is preserved across these
calls, leading to register corruption when the called functions
(__do_irq and __do_softirq) clobber r2.
As a result of this kernel crash during interrupt handling is seen and
the kernel fails to boot:
BUG: Unable to handle kernel data access on write at 0xc000000404697638
Faulting instruction address: 0xc0000000000181ec
Oops: Kernel access of bad area, sig: 11 [#1]
NIP [c0000000000181ec] __do_IRQ+0x6c/0xc0
With older GCC, the compiler would conservatively allocate
callee-saved registers (like r31) for values spanning function calls,
accidentally avoiding the bug:
<__do_IRQ>:
00 00 00 60 nop
a6 02 08 7c mflr r0
f8 ff e1 fb std r31,-8(r1)
f0 ff c1 fb std r30,-16(r1)
2d 03 10 06 pla r31,53297316
...
3d e8 ff 4b bl c0000000000165ac <__do_irq>
00 00 21 e8 ld r1,0(r1)
28 00 4d e9 ld r10,40(r13)
40 00 21 38 addi r1,r1,64
2a f9 aa 7f stdx r29,r10,r31
With newer GCC 14, the compiler uses r2 for such values, exposing the
missing clobber specification:
<__do_IRQ>:
00 00 00 6…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-93259 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-93259" on the vendor's site.
CVE-2026-93259 (Linux kernel)
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-93259 linux Fixed in: 6.12.111-1
- Ubuntu UBUNTU-CVE-2026-93259 linux-hwe-edge
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com