CVE-2026-68158

libceph: Fix multiplication overflow in decode_new_up_state_weight()

Published Aug 10, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed
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 ]

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4745-1 linux-6.12 security update
Debian DLA Debian DLA DLA-4777-1 linux security update
Ubuntu USN Ubuntu USN USN-8781-1 Linux kernel (NVIDIA Tegra) vulnerabilities
Ubuntu USN Ubuntu USN USN-8876-1 Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8875-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8877-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8878-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8879-1 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-8887-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8888-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8889-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8887-2 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8888-2 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8875-2 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8887-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8917-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8918-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9003-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9024-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9025-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9026-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9029-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-9040-1 Linux kernel (Low Latency NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9043-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9066-1 Linux kernel (HWE) vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-190
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Weaknesses CWE-680
Type Values Removed Values Added
Weaknesses CWE-125
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-680
Type Values Removed Values Added
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 ]
Title libceph: Fix multiplication overflow in decode_new_up_state_weight()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 8:58 PM
Reserved
Jul 30, 2026, 9:28 AM
Status
Received
Published
Aug 10, 2026, 1:20 PM
Modified
Oct 19, 2026, 9:17 PM
Severity
Moderate
Public date
Aug 10, 2026, 12:00 AM