CVE-2025-9300VulnerabilityPublished 21 Aug 2025

CVE-2025-9300: saitoha libsixel · Stack-based Buffer Overflow

Affects saitoha libsixelSource CVE Database V5

Not known to be exploited · CVSS 4.8 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

4.8Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Local
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

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

Attack Vector: Local: The vulnerable system 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 through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system 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 Vulnerable System 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 Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 21 Aug 2025
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 2026-10-25.

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 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
saitoha libsixel	Affected =1.10.0 =1.10.1 =1.10.2 =1.10.3	Fixed in–

AI-suggested

To mitigate CVE-2025-9300, European organizations should: 1) Immediately apply the official patch identified by commit 316c086e79d66b62c0c4bc66229ee894e4fdb7d1 to all affected libsixel versions (1.10.0 to 1.10.3). 2) Conduct an inventory of software and systems that utilize libsixel, including indirect dependencies in development tools and terminal emulators, to ensure comprehensive patching. 3) Restrict local access to systems running vulnerable libsixel versions by enforcing strict access controls, limiting user privileges, and monitoring for unauthorized local login attempts. 4) Implement application whitelisting and runtime protection mechanisms to detect and prevent exploitation attempts involving buffer overflow behaviors. 5) Enhance logging and monitoring around local user activities and image processing components to detect anomalous behavior indicative of exploitation attempts. 6) Educate system administrators and developers about the vulnerability and the importance of applying patches promptly, especially in environments where local access cannot be fully restricted. 7) Consider deploying endpoint detection and response (EDR) solutions capable of identifying exploitation techniques related to stack-based buffer overflows.

Description

A vulnerability was found in saitoha libsixel up to 1.10.3. Affected by this issue is the function sixel_debug_print_palette of the file src/encoder.c of the component img2sixel. The manipulation results in stack-based buffer overflow. The attack must be initiated from a local position. The exploit has been made public and could be used. The patch is identified as 316c086e79d66b62c0c4bc66229ee894e4fdb7d1. Applying a patch is advised to resolve this issue.

Impact

For European organizations, the impact of CVE-2025-9300 depends largely on the deployment of the libsixel library within their infrastructure. Organizations using software that incorporates libsixel for image encoding or terminal graphics rendering could face risks of local privilege escalation or denial of service if an attacker gains local access. This is particularly relevant for development environments, CI/CD pipelines, or specialized terminal applications that process sixel images. The vulnerability could be leveraged by malicious insiders or attackers who have already compromised a low-privilege account to escalate privileges or disrupt services. While the requirement for local access limits remote exploitation, the presence of publicly available exploit code increases the risk of lateral movement within networks. European sectors with high reliance on secure development environments, such as finance, critical infrastructure, and government agencies, should be vigilant. Additionally, organizations with remote desktop or terminal access services that might expose local user environments could be indirectly affected if attackers gain foothold through other means.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 21 Aug 2025, 13:32 UTC

Technical details

References

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