{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74438","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-15T05:44:03.897Z","datePublished":"2026-08-15T05:59:36.044Z","dateUpdated":"2026-08-17T05:47:12.124Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T05:47:12.124Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: sun4i-ss - Remove insecure and unused rng_alg\n\nRemove sun4i_ss_rng, as it is insecure and unused:\n\n- It has multiple vulnerabilities.  sun4i_ss_prng_seed() is missing\n  locking and has a buffer overflow.  sun4i_ss_prng_generate() fails to\n  fill the entire buffer with cryptographic random bytes, because it\n  rounds the destination length down and also doesn't actually wait for\n  the hardware to be ready before pulling bytes from it.\n\n- No user of this code is known.  It's usable only theoretically via the\n  \"rng\" algorithm type of AF_ALG.  But userspace actually just uses the\n  actual Linux RNG (/dev/random etc) instead.  And rng_algs don't\n  contribute entropy to the actual Linux RNG either.  (This may have\n  been confused with hwrng, which does contribute entropy.)\n\nThe sun4i_ss_prng_seed() buffer overflow was reported by Tianchu Chen\nand discovered by Atuin - Automated Vulnerability Discovery Engine\n\nThere's no point in fixing all these vulnerabilities individually when\nthis is unused code, so let's just remove it."}],"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:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable sun4i_ss_prng_seed() is reached only through the AF_ALG userspace crypto API (socket/bind/setsockopt ALG_SET_KEY/accept/recvmsg), which is a local syscall interface with no network-facing handler exposing this Allwinner PRNG.\nAC:L - On affected Allwinner systems with CONFIG_CRYPTO_DEV_SUN4I_SS_PRNG enabled, an attacker deterministically triggers the overflow by passing a seed longer than the 24-byte ss->seed buffer via ALG_SET_KEY; no race or external state is required, and concurrent seed/generate races are attacker-controlled.\nPR:L - AF_ALG RNG sockets are available to unprivileged local users without capabilities; only ALG_SET_DRBG_ENTROPY requires CAP_SYS_ADMIN. No root or namespace-spawned admin capability is needed to bind to sun4i_ss_rng and invoke the seed path.\nUI:N - Exploitation requires only the attacker's own PF_ALG socket operations; no victim must mount devices, open files, or perform any interactive action.\nS:U - The heap buffer overflow corrupts kernel memory within the sun4i-ss driver's context structure and adjacent slab objects, staying within kernel privilege domain; it does not cross VM, IOMMU, or sandbox boundaries.\nC:H - memcpy() with attacker-controlled slen past the 24-byte ss->seed array overwrites dbgfs_dir/dbgfs_stats pointers and subsequent kernel heap data, giving an out-of-bounds write that can be leveraged for arbitrary kernel memory disclosure.\nI:H - The unchecked slen in sun4i_ss_prng_seed() is a kernel heap buffer overflow past ss->seed[6], corrupting adjacent kernel objects and enabling controlled overwrite primitives suitable for privilege escalation or code execution.\nA:H - Heap corruption from the seed buffer overflow or concurrent unlocked seed()/locked generate() races can cause kernel oops/panic or hang, and the overflow is repeatable on demand via ALG_SET_KEY without authentication."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm/configs/sunxi_defconfig","drivers/crypto/allwinner/Kconfig","drivers/crypto/allwinner/sun4i-ss/Makefile","drivers/crypto/allwinner/sun4i-ss/sun4i-ss-core.c","drivers/crypto/allwinner/sun4i-ss/sun4i-ss-prng.c","drivers/crypto/allwinner/sun4i-ss/sun4i-ss.h"],"versions":[{"version":"b8ae5c7387ad075ee61e8c8774ce2bca46bc9236","lessThan":"2eafecaba1b46bb9774eaf3556619fd5b6a17c1c","status":"affected","versionType":"git"},{"version":"b8ae5c7387ad075ee61e8c8774ce2bca46bc9236","lessThan":"ee2458f8188732aa53a5d42f56e87bfad288b44e","status":"affected","versionType":"git"},{"version":"b8ae5c7387ad075ee61e8c8774ce2bca46bc9236","lessThan":"306ded31bfa00a69d25823a60d7c797170bfb4f8","status":"affected","versionType":"git"},{"version":"b8ae5c7387ad075ee61e8c8774ce2bca46bc9236","lessThan":"e4b7b9819811c4c51064c3d3d3c02f0be7491707","status":"affected","versionType":"git"},{"version":"b8ae5c7387ad075ee61e8c8774ce2bca46bc9236","lessThan":"c401492e01c7bfd38cf14c94d85c7efafe7d1a25","status":"affected","versionType":"git"},{"version":"b8ae5c7387ad075ee61e8c8774ce2bca46bc9236","lessThan":"9c8086d9511189c34dfa3f9e3a03f2bee12f56a5","status":"affected","versionType":"git"},{"version":"b8ae5c7387ad075ee61e8c8774ce2bca46bc9236","lessThan":"b2c41fa9dd8fc740c489e060b199165771f268d1","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm/configs/sunxi_defconfig","drivers/crypto/allwinner/Kconfig","drivers/crypto/allwinner/sun4i-ss/Makefile","drivers/crypto/allwinner/sun4i-ss/sun4i-ss-core.c","drivers/crypto/allwinner/sun4i-ss/sun4i-ss-prng.c","drivers/crypto/allwinner/sun4i-ss/sun4i-ss.h"],"versions":[{"version":"4.14","status":"affected"},{"version":"0","lessThan":"4.14","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":"5.15.212"},{"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/2eafecaba1b46bb9774eaf3556619fd5b6a17c1c"},{"url":"https://git.kernel.org/stable/c/ee2458f8188732aa53a5d42f56e87bfad288b44e"},{"url":"https://git.kernel.org/stable/c/306ded31bfa00a69d25823a60d7c797170bfb4f8"},{"url":"https://git.kernel.org/stable/c/e4b7b9819811c4c51064c3d3d3c02f0be7491707"},{"url":"https://git.kernel.org/stable/c/c401492e01c7bfd38cf14c94d85c7efafe7d1a25"},{"url":"https://git.kernel.org/stable/c/9c8086d9511189c34dfa3f9e3a03f2bee12f56a5"},{"url":"https://git.kernel.org/stable/c/b2c41fa9dd8fc740c489e060b199165771f268d1"}],"title":"crypto: sun4i-ss - Remove insecure and unused rng_alg","x_generator":{"engine":"bippy-1.2.0"}}}}