Dasel: Denial of service in dasel selector lexer due to infinite loop on unterminated regex literal

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-46378: 0.16% estimated exploitation activity in the next 30 days; percentile 5.41 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary dasel's selector lexer enters a non-terminating loop when tokenizing an unterminated regex pattern such as r/abc. A 2-byte input (r/) is sufficient to cause the tokenizer to consume 100% CPU on one core indefinitely. I confirmed the issue on v3.3.1 (fba653c7f248aff10f2b89fca93929b64707dfc8) and on master commit 0dd6132e0c58edbd9b1a5f7ffd00dfab1e6085ad. I also verified the same code path is present in v3.0.0 (648f83baf070d9e00db8ff312febef857ec090a3). No fix is available yet. Details The bug is in the matchRegexPattern closure within (Tokenizer).parseCurRune in selector/lexer/tokenize.go#L237-L247: When no closing / exists, peekRuneEqual returns false when pos = srcLen (because the bounds check at line 40 returns false for out-of-range positions). Since !false = true, the loop condition remains true and pos increments indefinitely. The function never returns. Notably, the same function already handles unterminated quoted strings by returning UnexpectedEOFError, but the regex…

Published by the source

19 May 2026, 20:09 UTC

Last modified by the source

19 May 2026, 20:09 UTC

Source last checked

26 Oct 2026, 15:22 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-m6xr-fvfg-5g64

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# Patch Next advisory brief: CVE-2026-46378

Advisory: Dasel: Denial of service in dasel selector lexer due to infinite loop on unterminated regex literal
IDs: CVE-2026-46378, GHSA-m6xr-fvfg-5g64
Record: https://patchnext.com/advisories/cve-2026-46378 (revision 1, source checked 26 Oct 2026, 15:22 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/tomwright/dasel/v3 3.10.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/tomwright/dasel/v3: affected >= 3.0.0, < 3.10.1; fixed in 3.10.1

## Suggested inspection (read-only)
- Go github.com/tomwright/dasel/v3: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/tomwright/dasel/v3.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-m6xr-fvfg-5g64 (GitHub-reviewed advisory GHSA-m6xr-fvfg-5g64 lists affected ranges: Go github.com/tomwright/dasel/v3 >=3.0.0 <3.10.1)

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