CVE-2026-12644: ts-deepmerge · Uncaught Exception
Affects ts-deepmergeSource CVE Database V5
Public exploit available · CVSS 6.9 Medium : upgrade to 8.0.0 as a priority.
Data as of 1 Nov 2026, 22:58 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 8.0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:PExploitation evidence
Disclosed: evidence found.
CVE published 19 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
CVSS exploit maturity: proof of concept public
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), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 1 Nov 2026.
What to do
Upgrade ts-deepmerge to 8.0.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| ts-deepmerge | Affected
| Fixed in
|
npmts-deepmergepkg:npm/ts-deepmergeOther threats | Affected
| Fixed in
|
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, avoid merging user-controlled input that may contain Object.prototype keys such as toString or valueOf with non-function values. Implement input validation or sanitization to prevent such keys from being processed by ts-deepmerge.
Description
Versions of the package ts-deepmerge before 8.0.0 are vulnerable to Uncaught Exception due to the improper handling of built-in Object.prototype methods (such as toString, valueOf). When user-controlled input contains these keys with non-function values, the resulting merged object becomes broken — any string context operation throws a TypeError, crashing the application.