CVE-2026-2659
Published: 18 February 2026
Summary
CVE-2026-2659 is a medium-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Squirrel-Lang Squirrel. Its CVSS base score is 4.8 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 1.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-16 (Memory Protection) and AC-6 (Least Privilege).
Deeper analysis
CVE-2026-2659 is a vulnerability in Squirrel scripting language versions up to 3.2, specifically affecting the SQFuncState::PopTarget function in the file src/squirrel/squirrel/sqfuncstate.cpp. The flaw is triggered by manipulation of the _target_stack argument, resulting in an out-of-bounds read. It is classified under CWE-119 (improper restriction of operations within the bounds of a memory buffer) and CWE-125 (out-of-bounds read), with a CVSS v3.1 base score of 3.3.
The attack requires local access (AV:L) with low privileges (PR:L), low complexity (AC:L), and no user interaction (UI:N), with unchanged scope (S:U). A local attacker can exploit it to cause a low-impact availability disruption (A:L), such as a denial of service, with no impact on confidentiality or integrity (C:N/I:N).
References indicate the issue was reported early to the project via GitHub issue #311 (https://github.com/albertodemichelis/squirrel/issues/311), but no response has been received and no patches are available. A public proof-of-concept exploit is disclosed at https://github.com/oneafter/0122/blob/main/i311/repro, with further details on VulDB (https://vuldb.com/?ctiid.346457, https://vuldb.com/?id.346457, https://vuldb.com/?submit.753163).
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-7643
Vulnerability details
A vulnerability was determined in Squirrel up to 3.2. Affected by this vulnerability is the function SQFuncState::PopTarget of the file src/squirrel/squirrel/sqfuncstate.cpp. Executing a manipulation of the argument _target_stack can lead to out-of-bounds read. It is possible to launch the attack…
more
on the local host. The exploit has been publicly disclosed and may be utilized. The project was informed of the problem early through an issue report but has not responded yet.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
OOB read in Squirrel scripting engine enables local low-priv adversary to trigger application crash (A:L only), directly mapping to application/system exploitation for endpoint DoS.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces hardware or software memory protection mechanisms that would block the out-of-bounds read in SQFuncState::PopTarget.
Requires validation of untrusted inputs such as the _target_stack argument before it reaches the vulnerable PopTarget function.
Limits process privileges so a local attacker cannot easily reach or exploit the Squirrel interpreter code path.