CVE-2026-68158
Received Received - Intake

Integer Overflow in Linux Kernel Ceph OSD Map Decoding

Publication date: 2026-08-10

Last updated on: 2026-08-10

Assigner: kernel.org

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 ]

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Meta Information

Published
2026-08-10
Last Modified
2026-08-10
Generated
2026-08-10
AI Q&A
2026-08-10
EPSS Evaluated
N/A
NVD
CVE-2026-68158
EUVD
EUVD-2026-55544

Affected Vendors & Products

Currently, no data is known.

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a multiplication overflow in the ceph library function decode_new_up_state_weight(). When processing a corrupted OSD map message, the function calculates the length of new_state incorrectly due to an overflow, leading to out-of-bounds memory access. The fix uses check_mul_overflow() to detect overflows and reject invalid messages.

Detection Guidance

This vulnerability involves corrupted CEPH_MSG_OSD_MAP messages triggering out-of-bounds memory access in the Linux kernel's libceph module. Detection requires monitoring for kernel logs indicating decode_new_up_state_weight() errors or osdmap corruption events. Check kernel logs with 'dmesg | grep ceph' or 'journalctl -k | grep ceph' for suspicious messages related to osdmap processing.

Impact Analysis

This vulnerability could allow attackers to trigger out-of-bounds memory reads by sending maliciously crafted CEPH_MSG_OSD_MAP messages. This may lead to crashes, data corruption, or potential privilege escalation in systems using the Linux kernel with ceph functionality.

Mitigation Strategies

Apply the kernel patch that replaces the vulnerable multiplication with check_mul_overflow() to prevent overflow-based out-of-bounds access. Update to a patched kernel version immediately. If patching is delayed, restrict network access to ceph services to trusted sources only as a temporary workaround.

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