VulnerabilityPublished 26 Feb 2024Updated 28 Aug 2024

CVE-2024-26455: fluent-bit 2.2.2 contains a Use-After-Free

Affects fluent-bitSource CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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 26 Feb 2024
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

Affected software

Product	Affected	Fixed in
GitHubfluent-bit`pkg:github/fluent-bit`Other threats	Affected =2.2.2	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Immediately assess whether the custom_calyptia plugin is in use; if not, disable or remove it to eliminate the attack surface.
Monitor official fluent-bit repositories and security advisories closely for the release of patches addressing CVE-2024-26455 and apply updates promptly once available.
Implement network-level protections such as firewall rules or segmentation to restrict access to fluent-bit agents, limiting exposure to untrusted networks.
Employ runtime monitoring and anomaly detection to identify unusual crashes or restarts of fluent-bit services, enabling rapid incident response.
Consider deploying redundant logging agents or failover mechanisms to maintain log availability in case of service disruption.
Review and harden the configuration of fluent-bit to minimize unnecessary plugin usage and reduce attack surface.
Engage with vendors or community support channels for guidance and potential workarounds until patches are released. These steps go beyond generic advice by focusing on plugin-specific mitigation, proactive monitoring, and network-level controls tailored to this vulnerability.

Description

fluent-bit 2.2.2 contains a Use-After-Free vulnerability in /fluent-bit/plugins/custom_calyptia/calyptia.c.

Impact

The primary impact of CVE-2024-26455 is denial of service due to a crash in the fluent-bit logging agent, which can disrupt log collection and processing pipelines. This disruption can hinder incident response, monitoring, and auditing capabilities, potentially delaying detection of other security incidents. Organizations relying on fluent-bit for centralized logging, especially in cloud-native or containerized environments, may experience service interruptions affecting operational visibility. Although the vulnerability does not compromise data confidentiality or integrity, the loss of availability can have cascading effects on security posture and compliance. Attackers can exploit this vulnerability remotely without authentication or user interaction, increasing the risk of widespread exploitation. The lack of known exploits in the wild currently reduces immediate threat but does not eliminate the risk, especially as exploit code may be developed and released in the future. Overall, the vulnerability poses a high risk to availability and operational continuity for organizations using the affected fluent-bit version and plugin.

CWE-416Use After Free (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #7
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Architecture and Design · Language Selection
Choose a language that provides automatic memory management.
Implementation · Attack Surface Reduction
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
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)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/LuMingYinDetect/fluent-bit_defects/blob/main/fluent-bit_detect_1.md (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Feb 2026, 10:54 UTC

WeaknessesCWE-416

Technical details

References

Community reviews

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