{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74578", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.917Z", "datePublished": "2026-08-16T08:20:32.055Z", "dateUpdated": "2026-08-17T05:48:57.219Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:48:57.219Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: algif_skcipher - force synchronous processing on trees without ctx->state\n\nThe AIO/async path in skcipher_recvmsg() passes the socket-wide ctx->iv\ndirectly into the skcipher request. After io_submit() the socket lock is\ndropped and the request is processed asynchronously, so a concurrent\nsendmsg(ALG_SET_IV) can overwrite ctx->iv and make the in-flight request\nrun under an attacker-controlled IV. For CTR/stream modes this is\nIV/keystream reuse and lets an unprivileged user recover the plaintext of\na concurrent operation.\n\nSnapshotting ctx->iv into per-request storage for the async path is not\nsufficient. For ciphers with statesize == 0 - which includes cbc and ctr -\nthe MSG_MORE inter-chunk IV chaining is carried solely by the in-place\nreq->iv writeback, which a snapshot redirects into per-request memory that\naf_alg_free_resources() releases on completion, silently producing wrong\noutput. Writing the IV back from the completion callback instead is not\npossible either: that would require lock_sock() there, but the callback can\nrun in softirq/atomic context, so it must not sleep.\n\nMake the operation synchronous instead, which removes both the IV race and\nany writeback race. This is equivalent to the upstream resolution, commit\nfcc77d33a34c (\"net: Remove support for AIO on sockets\"), which removed the\nAIO socket path across net/ entirely and so produces the same end state for\nthis file. This patch deviates from that commit deliberately: rather than\nremoving AIO socket support tree-wide, which would be far too invasive for\nstable, it removes only the AIO branch in crypto/algif_skcipher.c.\nio_submit() now completes synchronously; AF_ALG async is rarely used in\npractice.\n\nThe -EIOCBQUEUED check in skcipher_recvmsg() is now dead but harmless,\nand is left alone to keep the fix minimal.\n\nTested on 6.6.y: attacker IV injection dropped from 2296/200000 to 0/200000\nafter the change; MSG_MORE chunked CTR output bit-identical to single-shot." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Exploitation requires local syscalls on an AF_ALG skcipher socket (socket/bind/accept/sendmsg plus async recvmsg, io_submit, aio_read, or io_uring read); the bug is not reachable from remote network protocols.\nAC:L - The attacker fully controls the race by running concurrent threads or syscalls on the same socket, timing async recvmsg/io_submit against sendmsg(ALG_SET_IV); pre-fix testing achieved thousands of successful IV injections in 200000 attempts.\nPR:L - Any unprivileged local user can create and use AF_ALG skcipher sockets without CAP_NET_ADMIN or init-namespace root; only standard UNIX discretionary access to the target socket FD is required, which includes same-UID multi-threaded processes.\nUI:N - Exploitation is fully attacker-driven through direct syscalls and requires no victim interaction such as opening files, clicking links, or mounting filesystems.\nS:U - Impact is confined to cryptographic operations on the compromised AF_ALG socket within the attacker's security context; it does not cross VM, container, or kernel-user authority boundaries like KVM escape or IOMMU bypass.\nC:H - Concurrent IV injection on CTR/stream ciphers causes keystream reuse, letting an attacker recover the full plaintext of an in-flight decrypt/encrypt on the same keyed socket even when the key never leaves kernel memory.\nI:H - Attacker-controlled IV injection corrupts in-flight cipher output and breaks MSG_MORE CBC/CTR chaining (statesize==0), silently producing attacker-influenced ciphertext/plaintext and undermining cryptographic integrity of concurrent operations.\nA:N - The flaw causes information disclosure and silent cryptographic corruption but does not kernel panic, oops, hang, or reliably deny service; availability impact is none beyond possible application-level misbehavior." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "crypto/algif_skcipher.c" ], "versions": [ { "version": "e870456d8e7c8d57c059ea479b5aadbb55ff4c3a", "lessThan": "bf09b0be8e851f050e98da702d247c14d81b591a", "status": "affected", "versionType": "git" }, { "version": "e870456d8e7c8d57c059ea479b5aadbb55ff4c3a", "lessThan": "73dd3bf704ca6c20639de70c08e9a10bee904a95", "status": "affected", "versionType": "git" }, { "version": "e870456d8e7c8d57c059ea479b5aadbb55ff4c3a", "lessThan": "f1a87ca0843d74482402a206ea2dfb315ee9acbd", "status": "affected", "versionType": "git" }, { "version": "e870456d8e7c8d57c059ea479b5aadbb55ff4c3a", "lessThan": "7b91e51d0eb7cbb07f7f086f9176bd93dbbc85dd", "status": "affected", "versionType": "git" }, { "version": "e870456d8e7c8d57c059ea479b5aadbb55ff4c3a", "lessThan": "60eafc7b08c6689ea3ad39eff8d97aefc8a087c7", "status": "affected", "versionType": "git" }, { "version": "e870456d8e7c8d57c059ea479b5aadbb55ff4c3a", "lessThan": "d7860b682da55433b5da0591b0e4c1982ecd2689", "status": "affected", "versionType": "git" }, { "version": "e870456d8e7c8d57c059ea479b5aadbb55ff4c3a", "lessThan": "b05defc41b27c7d0c05c45f67bf5b91c28f93669", "status": "affected", "versionType": "git" }, { "version": "e870456d8e7c8d57c059ea479b5aadbb55ff4c3a", "lessThan": "fcc77d33a34cf271702e8daafb6c593e4626776d", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "crypto/algif_skcipher.c" ], "versions": [ { "version": "4.14", "status": "affected" }, { "version": "0", "lessThan": "4.14", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "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": "4.14", "versionEndExcluding": "5.10.261" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/bf09b0be8e851f050e98da702d247c14d81b591a" }, { "url": "https://git.kernel.org/stable/c/73dd3bf704ca6c20639de70c08e9a10bee904a95" }, { "url": "https://git.kernel.org/stable/c/f1a87ca0843d74482402a206ea2dfb315ee9acbd" }, { "url": "https://git.kernel.org/stable/c/7b91e51d0eb7cbb07f7f086f9176bd93dbbc85dd" }, { "url": "https://git.kernel.org/stable/c/60eafc7b08c6689ea3ad39eff8d97aefc8a087c7" }, { "url": "https://git.kernel.org/stable/c/d7860b682da55433b5da0591b0e4c1982ecd2689" }, { "url": "https://git.kernel.org/stable/c/b05defc41b27c7d0c05c45f67bf5b91c28f93669" }, { "url": "https://git.kernel.org/stable/c/fcc77d33a34cf271702e8daafb6c593e4626776d" } ], "title": "crypto: algif_skcipher - force synchronous processing on trees without ctx->state", "x_generator": { "engine": "bippy-1.2.0" } } } }