{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80560","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-26T14:34:25.767Z","datePublished":"2026-08-26T14:37:25.971Z","dateUpdated":"2026-08-27T05:01:48.838Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-27T05:01:48.838Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nopenrisc: signal: do not restore privileged SR bits on sigreturn\n\nrestore_sigcontext() copies the whole supervision register (SR) from the\nsignal frame and only clears SPR_SR_SM before the value is reloaded into\nthe hardware SR (through ESR and l.rfe) on the return to user space.  All\nother SR bits are left under user control.\n\nAn unprivileged task can thus return from a signal handler through a\ncrafted sigframe that clears SPR_SR_DME.  With the data MMU disabled the\nCPU performs no translation or protection on data accesses, so the task\ngains read and write access to arbitrary physical memory, a local\nprivilege escalation.  SPR_SR_IME, SPR_SR_SUMRA, SPR_SR_LEE, SPR_SR_EPH\nand the cache-enable bits are exposed the same way.  The ptrace GPR regset\nalready refuses any change to SR for exactly this reason.\n\nRestore only the arithmetic flag bits (F, CY, OV) from the signal frame\nand take every privileged control bit from the SR the kernel saved on\nsignal entry.\n\nVerified with qemu-system-or1k -M or1k-sim: before this change an\nunprivileged PoC clears SPR_SR_DME in rt_sigreturn and writes a marker to\nphysical address 0x03000000 (beyond the kernel's mem=32M); afterwards the\nsame PoC receives SIGSEGV and physical memory is unchanged."}],"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 flaw is only reachable through the local rt_sigreturn syscall path (userspace trap to _sys_call_handler, sys_rt_sigreturn, restore_sigcontext, then l.rfe); OpenRISC signal handling has no network, adjacent-wireless, or physical-device entry point.\nAC:L - Exploitation is deterministic because the attacker fully controls the rt_sigframe SR field and can invoke rt_sigreturn directly; the fix author verified an unprivileged PoC on qemu-system-or1k that clears SPR_SR_DME and writes arbitrary physical memory.\nPR:L - Any unprivileged local process can call rt_sigreturn with a crafted sigframe on its own stack; the path performs only access_ok/copy_from_user checks and has no capability, authentication, or init-namespace root requirement.\nUI:N - No separate victim interaction is needed; the attacker can self-send a signal or directly syscall rt_sigreturn with a forged stack frame in their own process without requiring another user to mount, plug in, or approve anything.\nS:U - This is standard host-kernel privilege escalation by restoring attacker-controlled CPU privilege bits on sigreturn; it does not cross a VM guest/host, container sandbox, or IOMMU security boundary despite granting direct physical memory access.\nC:H - Clearing SPR_SR_DME disables data MMU translation and protection, allowing an unprivileged task to read arbitrary physical addresses including kernel memory; other exposed SR bits (SPR_SR_IME, SPR_SR_SUMRA, cache enables) further broaden privileged-state disclosure.\nI:H - With SPR_SR_DME cleared the CPU performs unprotected physical data accesses, giving arbitrary read/write to all of RAM; the fix commit PoC writes a marker beyond the kernel mem=32M reservation, demonstrating direct integrity compromise and local root escalation.\nA:H - Arbitrary physical memory writes can corrupt kernel text, data, or device MMIO and trigger oops or panic; manipulating privileged SR and cache-control bits can also destabilize the system even when full exploitation is not attempted."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/openrisc/include/asm/processor.h","arch/openrisc/kernel/signal.c"],"versions":[{"version":"ac689eb7f9d4e270d1365853b82eece669387e2c","lessThan":"bc2e24ba6e167ccf374a197457aa5640a802f429","status":"affected","versionType":"git"},{"version":"ac689eb7f9d4e270d1365853b82eece669387e2c","lessThan":"cf1b5514ddf9df098ce7e3741fc9679fd85a4ec6","status":"affected","versionType":"git"},{"version":"ac689eb7f9d4e270d1365853b82eece669387e2c","lessThan":"cd8b43a71755c516f5c1f265a103438ae9ab15be","status":"affected","versionType":"git"},{"version":"ac689eb7f9d4e270d1365853b82eece669387e2c","lessThan":"b4d73c3848bae9084fa8b9b2aa76d99a7d8eb17d","status":"affected","versionType":"git"},{"version":"ac689eb7f9d4e270d1365853b82eece669387e2c","lessThan":"89a91b30685c0493b0fa2b47d0ab41061a63069d","status":"affected","versionType":"git"},{"version":"ac689eb7f9d4e270d1365853b82eece669387e2c","lessThan":"a88d688be8d7f03cbf927f2ab454ea9fa58d2979","status":"affected","versionType":"git"},{"version":"ac689eb7f9d4e270d1365853b82eece669387e2c","lessThan":"212fc482ddd7f9ccdd74a05eab1cac849350dcd6","status":"affected","versionType":"git"},{"version":"ac689eb7f9d4e270d1365853b82eece669387e2c","lessThan":"32ef1b30ad736519f7a207bcc2986f3d4129d972","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/openrisc/include/asm/processor.h","arch/openrisc/kernel/signal.c"],"versions":[{"version":"3.1","status":"affected"},{"version":"0","lessThan":"3.1","status":"unaffected","versionType":"semver"},{"version":"5.10.266","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.217","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.184","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.153","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.105","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.46","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.10","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":"3.1","versionEndExcluding":"5.10.266"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"5.15.217"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.1.184"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.6.153"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.12.105"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.18.46"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"7.1.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/bc2e24ba6e167ccf374a197457aa5640a802f429"},{"url":"https://git.kernel.org/stable/c/cf1b5514ddf9df098ce7e3741fc9679fd85a4ec6"},{"url":"https://git.kernel.org/stable/c/cd8b43a71755c516f5c1f265a103438ae9ab15be"},{"url":"https://git.kernel.org/stable/c/b4d73c3848bae9084fa8b9b2aa76d99a7d8eb17d"},{"url":"https://git.kernel.org/stable/c/89a91b30685c0493b0fa2b47d0ab41061a63069d"},{"url":"https://git.kernel.org/stable/c/a88d688be8d7f03cbf927f2ab454ea9fa58d2979"},{"url":"https://git.kernel.org/stable/c/212fc482ddd7f9ccdd74a05eab1cac849350dcd6"},{"url":"https://git.kernel.org/stable/c/32ef1b30ad736519f7a207bcc2986f3d4129d972"}],"title":"openrisc: signal: do not restore privileged SR bits on sigreturn","x_generator":{"engine":"bippy-1.2.0"}}}}