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Public proof of conceptFix available

CVE-2026-12644

A public proof of concept exists; no exploitation attested.

  • Published2026-06-19
  • Fixed in8.0.0
  • WeaknessCWE-248

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2026-06-1906:17CVE publishedNVD

Versions per branch

OSV
ts-deepmerge
BranchAffectedFixed in
8.0< 8.0.08.0.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As snyk, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • ts-deepmerge
    Affected
    • < 8.0.0fixed in 8.0.0semver

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-06-19

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • ts-deepmergeTuxCare:npmfrom 7.0.0-tuxcare.0 · fixed in 7.0.0-tuxcare.1
  • ts-deepmergeTuxCare:npmfrom 7.0.2-tuxcare.0 · fixed in 7.0.2-tuxcare.1

Full record on NVD

Fix

  1. Update ts-deepmerge to 8.0.0

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionpoc2026-06-22
  • CNACVSS 4.05.5known since 2026-10-23
  • CNACVSS 3.15.3known since 2026-10-23
  • CISA-ADPweakness (CWE)CWE-2482026-06-22
  • CNAweakness (CWE)CWE-248known since 2026-10-23
  • FIRST EPSSEPSS score0.5 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryMODERATE2026-06-19

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS 4.0 vector
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
Published
2026-06-19
Last Modified
2026-06-23
NVD status
Deferred
GitHub Advisory
GHSA-87mf-gv2c-c62c

Frequently asked questions

What is CVE-2026-12644?

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.

Is CVE-2026-12644 actively exploited?

A proof-of-concept exploit exists for CVE-2026-12644, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-12644?

CVE-2026-12644 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

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