VulnerabilityPublished 24 Jun 2026Updated 19 Oct 2026

CVE-2026-52958: Linux kernel · libceph: Fix potential out-of-bounds access in osdmap_decode()

Affects Linux kernelSource CVE Database V5

Not known to be exploited · CVSS 9.1 Critical · fixed in ee933694645dac062d65fc2743f92bc06fa0db6b : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

9.1Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS

0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers can reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch

Available – fixed in ee933694645dac062d65fc2743f92bc06fa0db6b, e7187f33c02488697ec0d01d82bf7a3f8deaba8f, 8713bbc4b2b9ad78f803978e54b7e49dd21bd9be +5

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ dcbc919a5dc8c2629684a113a90c0b6fe10c3462, < ee933694645dac062d65fc2743f92bc06fa0db6b	Fixed in ee933694645dac062d65fc2743f92bc06fa0db6b
LinuxLinux	Affected ≥ dcbc919a5dc8c2629684a113a90c0b6fe10c3462, < e7187f33c02488697ec0d01d82bf7a3f8deaba8f	Fixed in e7187f33c02488697ec0d01d82bf7a3f8deaba8f
LinuxLinux	Affected ≥ dcbc919a5dc8c2629684a113a90c0b6fe10c3462, < 8713bbc4b2b9ad78f803978e54b7e49dd21bd9be	Fixed in 8713bbc4b2b9ad78f803978e54b7e49dd21bd9be
LinuxLinux	Affected ≥ dcbc919a5dc8c2629684a113a90c0b6fe10c3462, < 48df98d12b15360cd56af5c1f460307b340c1197	Fixed in 48df98d12b15360cd56af5c1f460307b340c1197
LinuxLinux	Affected ≥ dcbc919a5dc8c2629684a113a90c0b6fe10c3462, < 36a79759a288961b1ff28a68ec2d1f56f6848098	Fixed in 36a79759a288961b1ff28a68ec2d1f56f6848098
LinuxLinux	Affected ≥ dcbc919a5dc8c2629684a113a90c0b6fe10c3462, < 35d0ed82d03e5ee77ea4f31f20e29562a7721649	Fixed in 35d0ed82d03e5ee77ea4f31f20e29562a7721649

Description

In the Linux kernel, the following vulnerability has been resolved: libceph: Fix potential out-of-bounds access in osdmap_decode() When decoding osd_state and osd_weight from an incoming osdmap in osdmap_decode(), both are decoded for each osd, i.e., map->max_osd times. The ceph_decode_need() check only accounts for sizeof(*map->osd_weight) once. This can potentially result in an out-of-bounds memory access if the incoming message is corrupted such that the max_osd value exceeds the actual content of the osdmap message. This patch fixes the issue by changing the corresponding part in the ceph_decode_need() check to account for map->max_osd*sizeof(*map->osd_weight).

CWE-125Out-of-bounds Read (opens in a new tab)
Base weaknessCWE Top 25 (2025): #8
The product reads data past the end, or before the beginning, of the intended buffer.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design · Language Selection
Use a language that provides appropriate memory abstractions.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overread Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

WeaknessesCWE-125

Technical details

References

Community reviews

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