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Fencer Vulns
high 7.5

CVE-2026-44635 json

Kysely: JSON-path traversal injection via unsanitized path-leg metacharacters in `JSONPathBuilder.key()` / `.at()`

published 2026-05-11 5 mo ago modified 2026-10-26 13 d ago also GHSA-pv5w-4p9q-p3v2 , EUVD-2026-32623

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

Kysely is a type-safe TypeScript SQL query builder. From 0.26.0 to 0.28.16, DefaultQueryCompiler.visitJSONPathLeg does not escape JSON-path metacharacters (., [, ], *, **, ?). When attacker-controlled input flows into eb.ref(col, '->$').key(input) or .at(input) — including type-safe code where the JSON column is shaped like Record<string, T> so K extends string is the inferred type — every dot becomes a path-leg separator, letting an attacker traverse from the intended key into sibling and child fields the developer never meant to expose. The result is read access (and, in update statements, write access) to JSON sub-fields outside the intended scope across MySQL, PostgreSQL ->$/->>$, and SQLite. This vulnerability is fixed in 0.28.17.

Patch / fix

  • npm kysely 0.28.17

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/kysely-org/kysely/security/advisories/GHSA-pv5w-4p9q-p3v2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm kysely
>=0.26.0, <0.28.17
0.28.17

Affected products

  • kysely-org kysely

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-89 Improper Neutralization of Special Elements used in an SQL Command
  • CWE-915 Improperly Controlled Modification of Dynamically-Determined Object Attributes
  • CWE-1284 Improper Validation of Specified Quantity in Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.