CVE-2026-12644
ts-deepmerge: Prototype Method Override leads to DoS
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2026-12644- CVSS 4.0
- 6.9 Medium
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:P - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P - Weakness
- CWE-248, CWE-248
- Updated
- 2026-11-02
EUVDEUVD-2026-37991
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.
- Record
EUVD-2026-37991- CVSS 4.0
- 6.9 Medium
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:P - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-87mf-gv2c-c62c
ts-deepmerge: Prototype Method Override leads to DoS
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.
- Record
GHSA-87mf-gv2c-c62c- CVSS 4.0
- 5.5 Medium
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:P - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-248
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-12644- CVSS 4.0
- 5.5 Medium
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:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-248
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2026-12644- CVSS 4.0
- 5.5 Medium
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:P - Weakness
- CWE-248
- Updated
- 2026-11-02
OSVGHSA-87mf-gv2c-c62c
ts-deepmerge: Prototype Method Override leads to DoS
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.
- Record
GHSA-87mf-gv2c-c62c- CVSS 4.0
- 5.5 Medium
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:P - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-248
- Updated
- 2026-11-02
OSVCLSA-2026-1792473266 No score
TuxCare security update for ts-deepmerge (1 CVE)
TuxCare rebuilt ts-deepmerge to address 1 CVE. Fixed in 7.0.0-tuxcare.1.
- Record
CLSA-2026-1792473266- Updated
- 2026-11-02
OSVCLSA-2026-1792490574 No score
TuxCare security update for ts-deepmerge (1 CVE)
TuxCare rebuilt ts-deepmerge to address 1 CVE. Fixed in 7.0.2-tuxcare.1.
- Record
CLSA-2026-1792490574- Updated
- 2026-11-02
Affected packages
| Package | Affected | Fixed |
|---|---|---|
ts-deepmergenpm |
before 8.0.0 | 8.0.0 |
ts-deepmergeTuxCare:npm |
7.0.0-tuxcare.0 up to 7.0.0-tuxcare.1, plus listed versions 7.0.0 |
7.0.0-tuxcare.1 |
ts-deepmergeTuxCare:npm |
7.0.2-tuxcare.0 up to 7.0.2-tuxcare.1, plus listed versions 7.0.2 |
7.0.2-tuxcare.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-12644 is a medium vulnerability (CVSS 6.9) in ts-deepmerge, published June 19, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.51%, the 43rd percentile. Fixed in ts-deepmerge 8.0.0.
References
security.snyk.io/vuln/SNYK-JS-TSDEEPMERGE-17339141
gist.github.com/igorg1312/775fa00114c4d47df6ae0551779ab407
github.com/voodoocreation/ts-deepmerge/commit/305a05831a462fb2c353d3cbbff55a0733286f8c
nvd.nist.gov/vuln/detail/CVE-2026-12644