CVE-2026-80560

HIGHCVSS 7.8/10

Last modified

CVE-2026-80560 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: openrisc: signal: do not restore privileged SR bits on sigreturn restore_sigcontext() copies the whole supervision register (SR) from the signal frame and only clears SPR_SR_SM before the value is reloaded into the hardware SR (through ESR and l.rfe) on the return to user space. All other SR bits are left under user control. An unprivileged task can thus return from a signal handler through a crafted sigframe that clears SPR_SR_DME.

Description

In the Linux kernel, the following vulnerability has been resolved: openrisc: signal: do not restore privileged SR bits on sigreturn restore_sigcontext() copies the whole supervision register (SR) from the signal frame and only clears SPR_SR_SM before the value is reloaded into the hardware SR (through ESR and l.rfe) on the return to user space. All other SR bits are left under user control. An unprivileged task can thus return from a signal handler through a crafted sigframe that clears SPR_SR_DME. With the data MMU disabled the CPU performs no translation or protection on data accesses, so the task gains read and write access to arbitrary physical memory, a local privilege escalation. SPR_SR_IME, SPR_SR_SUMRA, SPR_SR_LEE, SPR_SR_EPH and the cache-enable bits are exposed the same way. The ptrace GPR regset already refuses any change to SR for exactly this reason. Restore only the arithmetic flag bits (F, CY, OV) from the signal frame and take every privileged control bit from the SR the kernel saved on signal entry. Verified with qemu-system-or1k -M or1k-sim: before this change an unprivileged PoC clears SPR_SR_DME in rt_sigreturn and writes a marker to physical address 0x03000000 (beyond the kernel's mem=32M); afterwards the same PoC receives SIGSEGV and physical memory is unchanged.

Metrics

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= ac689eb7f9d4e270d1365853b82eece669387e2c, < bc2e24ba6e167ccf374a197457aa5640a802f429; >= ac689eb7f9d4e270d1365853b82eece669387e2c, < cf1b5514ddf9df098ce7e3741fc9679fd85a4ec6; >= ac689eb7f9d4e270d1365853b82eece669387e2c, < cd8b43a71755c516f5c1f265a103438ae9ab15be; >= ac689eb7f9d4e270d1365853b82eece669387e2c, < b4d73c3848bae9084fa8b9b2aa76d99a7d8eb17d; >= ac689eb7f9d4e270d1365853b82eece669387e2c, < 89a91b30685c0493b0fa2b47d0ab41061a63069d; >= ac689eb7f9d4e270d1365853b82eece669387e2c, < a88d688be8d7f03cbf927f2ab454ea9fa58d2979; >= ac689eb7f9d4e270d1365853b82eece669387e2c, < 212fc482ddd7f9ccdd74a05eab1cac849350dcd6; >= ac689eb7f9d4e270d1365853b82eece669387e2c, < 32ef1b30ad736519f7a207bcc2986f3d4129d972
LinuxLinux3.1

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-80560?
In the Linux kernel, the following vulnerability has been resolved: openrisc: signal: do not restore privileged SR bits on sigreturn restore_sigcontext() copies the whole supervision register (SR) from the signal frame and only clears SPR_SR_SM before the value is reloaded into the hardware SR (through ESR and l.rfe) on the return to user space. All other SR bits are left under user control. An unprivileged task can thus return from a signal handler through a crafted sigframe that clears SPR_SR_DME. With the data MMU disabled the CPU performs no translation or protection on data accesses, so the task gains read and write access to arbitrary physical memory, a local privilege escalation. SPR_SR_IME, SPR_SR_SUMRA, SPR_SR_LEE, SPR_SR_EPH and the cache-enable bits are exposed the same way. The ptrace GPR regset already refuses any change to SR for exactly this reason. Restore only the arithmetic flag bits (F, CY, OV) from the signal frame and take every privileged control bit from the SR the kernel saved on signal entry. Verified with qemu-system-or1k -M or1k-sim: before this change an unprivileged PoC clears SPR_SR_DME in rt_sigreturn and writes a marker to physical address 0x03000000 (beyond the kernel's mem=32M); afterwards the same PoC receives SIGSEGV and physical memory is unchanged.
How severe is CVE-2026-80560?
CVE-2026-80560 has a CVSS score of 7.8/10 (HIGH severity).
How do I fix CVE-2026-80560?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

Are you affected by CVE-2026-80560?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST