VulnerabilityPublished 23 Jan 2026Updated 19 Oct 2026

CVE-2026-22990: Linux kernel · libceph: replace overzealous BUG_ON in osdmap_apply_incremental()

Affects Linux kernelSource CVE Database V5

Not known to be exploited · CVSS 7.5 High · fixed in e00c3f71b5cf75681dbd74ee3f982a99cb690c2b : patch Linux kernel soon.

Data as of 26 Oct 2026, 12:42 UTC

CVSS 3.1 base score

7.5High

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

EPSS

0.4% chance of exploitation in 30 days – higher than 34% 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, 2026-06-16.

Patch

Available – fixed in e00c3f71b5cf75681dbd74ee3f982a99cb690c2b, d3613770e2677683e65d062da5e31f48c409abe9, 6348d70af847b79805374fe628d3809a63fd7df3 +4

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
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: None: There is no loss of confidentiality within the impacted component.
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 23 Jan 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 ≥ f24e9980eb860d8600cbe5ef3d2fd9295320d229, < e00c3f71b5cf75681dbd74ee3f982a99cb690c2b	Fixed in e00c3f71b5cf75681dbd74ee3f982a99cb690c2b
LinuxLinux	Affected ≥ f24e9980eb860d8600cbe5ef3d2fd9295320d229, < d3613770e2677683e65d062da5e31f48c409abe9	Fixed in d3613770e2677683e65d062da5e31f48c409abe9
LinuxLinux	Affected ≥ f24e9980eb860d8600cbe5ef3d2fd9295320d229, < 6348d70af847b79805374fe628d3809a63fd7df3	Fixed in 6348d70af847b79805374fe628d3809a63fd7df3
LinuxLinux	Affected ≥ f24e9980eb860d8600cbe5ef3d2fd9295320d229, < 9aa0b0c14cefece078286d78b97d4c09685e372d	Fixed in 9aa0b0c14cefece078286d78b97d4c09685e372d
LinuxLinux	Affected ≥ f24e9980eb860d8600cbe5ef3d2fd9295320d229, < 6c6cec3db3b418c4fdf815731bc39e46dff75e1b	Fixed in 6c6cec3db3b418c4fdf815731bc39e46dff75e1b
LinuxLinux	Affected ≥ f24e9980eb860d8600cbe5ef3d2fd9295320d229, < 6afd2a4213524bc742b709599a3663aeaf77193c	Fixed in 6afd2a4213524bc742b709599a3663aeaf77193c

AI-suggested

A fix is available and has been applied in the Linux kernel source code as indicated by the listed fixed commit versions. Users should update their Linux kernel to a version including these fixes to prevent kernel crashes caused by this issue.

Description

CVE-2026-22990 is a high-severity vulnerability in the Linux kernel's libceph component. It involves an overzealous BUG_ON check in the osdmap_apply_incremental() function that triggers a kernel BUG when the incremental osdmap epoch is unexpectedly different. The fix replaces this BUG_ON with logic that simply declares the incremental osdmap invalid, preventing unnecessary kernel crashes.

Impact

The vulnerability can cause a denial of service by crashing the Linux kernel due to the BUG_ON assertion firing when encountering corrupted or malicious osdmap data. There is no impact on confidentiality or integrity, but availability is affected due to kernel crashes.

Summary

This vulnerability in the Linux kernel's libceph module arises from an overly aggressive BUG_ON assertion in the osdmap_apply_incremental() function. When the osdmap is corrupted such that the incremental osdmap epoch does not match the expected value, the kernel would BUG (crash). The patch changes this behavior to avoid a kernel crash by marking the incremental osdmap as invalid instead. This prevents denial of service caused by kernel panics triggered by malformed or malicious osdmap data.

CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Regular Expression Exponential Blowup (opens in a new tab)
Sustained Client Engagement (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 12:07 UTC

WeaknessesCWE-400

Technical details

References

Community reviews

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