EUVD-2026-59580
GHSA-m4qf-hpr2-qv3g
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Network-triggered but requires niche rxgk in use plus a timing-sensitive UAF race (AC:H); no auth needed (PR:N); realistic impact is limited memory disclosure and DoS, not integrity loss.
Primary rating from Vendor (Linux).
CVSS VectorVendor: Linux
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
5DescriptionCVE.org
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix UAF in rxgk_issue_challenge()
Fix rxgk_issue_challenge() to free the page containing the challenge content after invoking the tracepoint as the whdr passed to the tracepoint points into the page just freed.
AnalysisAI
Memory corruption in the Linux kernel's rxrpc networking subsystem (rxgk/GSS Kerberos security class) affects kernels from 6.16 onward, where rxgk_issue_challenge() frees the page holding challenge content before a tracepoint reads the wire header (whdr) that still points into that freed page, creating a use-after-free. The flaw is patched in stable releases 6.18.40, 7.1.5 and 7.2-rc1, and is triggerable only where the rxrpc RxGK security class is active (primarily kAFS deployments). …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the target Linux system to have AF_RXRPC loaded and actively using the rxgk (GSS/Kerberos) security class - i.e., a kAFS/AFS deployment - and to reach the rxgk_issue_challenge() path during Rx connection challenge issuance with the relevant rxrpc tracepoint enabled/consumed. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The recorded CVSS 9.8 (AV:N/AC:L/PR:N/UI:N/C:H/I:H/A:H) is the common NVD-style auto-maximized score for kernel CVEs and materially overstates real-world risk here. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker able to speak the Rx protocol to a target running kAFS/rxgk initiates connection setup so the server calls rxgk_issue_challenge(), racing to influence or observe the freed page as the tracepoint reads whdr from memory that has already been released. Success would most plausibly leak fragments of kernel memory or crash the machine rather than yield reliable code execution, and no public exploit is known to exist. |
| Remediation | Vendor-released patch: update to Linux kernel 6.18.40, 7.1.5, or 7.2-rc1 (or later) which reorder the page free to occur after the tracepoint consumes whdr; apply the stable commits 844b8525, 83bb0ed0 or 107a4cb0 if backporting. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory systems running vulnerable Linux kernel versions (6.16-6.18.39, 7.0.x, 7.1.0-7.1.4) with rxrpc or kAFS enabled, prioritizing kAFS infrastructure. …
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External POC / Exploit Code
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