CVE-2026-74433

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74433", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.896Z", "datePublished": "2026-08-15T05:59:32.823Z", "dateUpdated": "2026-08-17T05:47:07.711Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:47:07.711Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix UAF in rxgk_issue_challenge()\n\nFix rxgk_issue_challenge() to free the page containing the challenge\ncontent after invoking the tracepoint as the whdr passed to the tracepoint\npoints into the page just freed."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - The bug is in rxgk_issue_challenge() on the RxRPC server path reached when a remote UDP RxRPC DATA packet starts a new call; packets enter via rxrpc_encap_rcv() and the I/O thread, then conn_event processing issues an RxGK challenge during the pre-auth handshake on internet-facing AFS/RxGK servers.\nAC:L - Once an RxGK-enabled AFS kernel server is reachable, an attacker can reliably trigger rxgk_issue_challenge() by sending a valid incoming DATA packet with security index YFS-RxGK; the UAF is deterministic on each successful challenge transmission and does not depend on winning a race.\nPR:N - The vulnerable code runs during initial server-side connection setup before client credentials are verified: an unauthenticated remote peer that can reach the RxRPC UDP port can force challenge issuance without any local account, capability, or namespace privilege on the target.\nUI:N - Exploitation requires only network packets to the RxRPC listener; no victim user action such as opening files, mounting AFS, or enabling tracing is needed for the server to automatically enter the challenging path and hit the bug.\nS:U - Impact is confined to kernel memory integrity and availability on the AFS/RxRPC server host; it does not by itself cross a VM, container, or IOMMU security boundary, though it may enable local privilege escalation on that host.\nC:H - This is a use-after-free: __free_page() releases the challenge buffer before trace_rxrpc_tx_packet() dereferences whdr pointing into that page, enabling reads of freed slab/page memory and potential disclosure of kernel heap contents exploitable for KASLR bypass.\nI:H - UAF on the challenge transmit path can be leveraged with heap grooming to obtain controlled reuse of the freed page and build arbitrary kernel write or control-flow hijack primitives, not merely a bounded protocol corruption.\nA:H - Reading or reusing freed kernel pages during challenge handling can provoke kernel oops/panic or wedged RxRPC/AFS service state; repeated remote triggering of the handshake can deny availability of the file service even without full exploitation."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/rxrpc/rxgk.c"], "versions": [{"version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a", "lessThan": "844b8525ce503405c462ad67f750bec648720397", "status": "affected", "versionType": "git"}, {"version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a", "lessThan": "83bb0ed050e2ad9453d8ef50e4d6e624eac6eed8", "status": "affected", "versionType": "git"}, {"version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a", "lessThan": "107a4cb0d47e735830f852d83970d5c81f8e1e08", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/rxrpc/rxgk.c"], "versions": [{"version": "6.16", "status": "affected"}, {"version": "0", "lessThan": "6.16", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "6.18.40"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/844b8525ce503405c462ad67f750bec648720397"}, {"url": "https://git.kernel.org/stable/c/83bb0ed050e2ad9453d8ef50e4d6e624eac6eed8"}, {"url": "https://git.kernel.org/stable/c/107a4cb0d47e735830f852d83970d5c81f8e1e08"}], "title": "rxrpc: Fix UAF in rxgk_issue_challenge()", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/rxrpc/rxgk.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "844b8525ce503405c462ad67f750bec648720397", "status": "affected", "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a", "versionType": "git"}, {"lessThan": "83bb0ed050e2ad9453d8ef50e4d6e624eac6eed8", "status": "affected", "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a", "versionType": "git"}, {"lessThan": "107a4cb0d47e735830f852d83970d5c81f8e1e08", "status": "affected", "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/rxrpc/rxgk.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.16"}, {"lessThan": "6.16", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.40", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.5", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix UAF in rxgk_issue_challenge()\n\nFix rxgk_issue_challenge() to free the page containing the challenge\ncontent after invoking the tracepoint as the whdr passed to the tracepoint\npoints into the page just freed."}], "id": "CVE-2026-74433", "lastModified": "2026-08-17T06:19:38.920", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-15T06:22:45.417", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/107a4cb0d47e735830f852d83970d5c81f8e1e08"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/83bb0ed050e2ad9453d8ef50e4d6e624eac6eed8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/844b8525ce503405c462ad67f750bec648720397"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

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