{"cve":"CVE-2026-80560","nvd":{"published":"2026-08-26T15:17:10.850","modified":"2026-08-27T06:17:40.650","status":"Received","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/212fc482ddd7f9ccdd74a05eab1cac849350dcd6","https://git.kernel.org/stable/c/32ef1b30ad736519f7a207bcc2986f3d4129d972","https://git.kernel.org/stable/c/89a91b30685c0493b0fa2b47d0ab41061a63069d","https://git.kernel.org/stable/c/a88d688be8d7f03cbf927f2ab454ea9fa58d2979","https://git.kernel.org/stable/c/b4d73c3848bae9084fa8b9b2aa76d99a7d8eb17d"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:17.453294893+00:00"},"epss":{"cve":"CVE-2026-80560","score":0.00176,"percentile":0.07074,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}