VulnerabilityPublished 23 Feb 2026

CVE-2025-61146: libsixel · Memory Leak

Affects libsixelSource CVE Database V5

Not known to be exploited · CVSS 4.0 Medium : upgrade to 1.8.8 when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

4.0Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.8.8

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

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

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

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
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: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Feb 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 saitoha/libsixel to 1.8.8.

Affected software

Product	Affected	Fixed in
GitHubsaitoha/libsixel`pkg:github/saitoha/libsixel`Other threats	Affected <1.8.8	Fixed in 1.8.8

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

AI-suggested

If you cannot patch yet, limiting the use of vulnerable libsixel versions in critical or resource-constrained environments is advisable. Employ resource monitoring and limits (e.g., cgroups on Linux) to detect and contain abnormal memory usage by processes utilizing libsixel. Consider sandboxing or isolating applications that invoke libsixel to prevent system-wide impact. For developers, reviewing and updating code to ensure proper memory management in malloc_stub.c or replacing libsixel with alternative libraries without this vulnerability can be effective. Additionally, restricting local access to trusted users and processes reduces exploitation risk. Regularly auditing systems for signs of memory leaks or performance degradation related to image processing tasks will help in early detection.

Description

saitoha libsixel until v1.8.7 was discovered to contain a memory leak via the component malloc_stub.c.

Impact

The primary impact of CVE-2025-61146 is on system availability due to memory exhaustion caused by the leak. In environments where libsixel is used extensively, such as servers processing large batches of images or embedded devices with limited memory, this could lead to degraded performance, application crashes, or system instability. Since the vulnerability does not affect confidentiality or integrity, data breaches or unauthorized modifications are unlikely. However, denial of service conditions could disrupt business operations, especially in critical systems relying on continuous image processing or terminal graphics rendering. The local attack vector and no privilege requirement mean that any local user or process could potentially trigger the leak, posing a risk in multi-tenant or shared systems.

CWE-401Missing Release of Memory after Effective Lifetime (opens in a new tab)
Variant weaknessLikelihood of exploit: Medium
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
Implementation · Libraries or Frameworks
Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Architecture and Design · Build and Compilation
Consider using the Boehm-Demers-Weiser garbage collector (bdwgc), which can help avoid leaks.
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

AI analysisMachine-generated, updated 3 Mar 2026, 01:46 UTC

WeaknessesCWE-401

Technical details

References

Community reviews

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