CVE-2020-26302 json
is_js vulnerable to Regular Expression Denial of Service
published 3y ago modified 4mo ago also GHSA-pvrw-g6fx-mcx2 , EUVD-2023-2119
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.9%
- EPSS 0.9% chance of exploitation in 30 days, percentile 60%
- public exploits
- 0
- none known
Summary
is.js is a general-purpose check library. Versions 0.9.0 and prior contain one or more regular expressions that are vulnerable to Regular Expression Denial of Service (ReDoS). is.js uses a regex copy-pasted from a gist to validate URLs. Trying to validate a malicious string can cause the regex to loop “forever." This vulnerability was found using a CodeQL query which identifies inefficient regular expressions. is.js has no patch for this issue.
Is CVE-2020-26302 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- last yr.
Exploit prediction
0.92% chance of exploitation in the next 30 days, higher than 60% of all scored CVEs (FIRST EPSS, 2026-11-09).
Exploits and checks
- securitylab.github.com https://securitylab.github.com/advisories/GHSL-2020-295-redos-is.js 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:N/I:N/A:H |
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| GitHub | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | is_js | <=0.9.0 |
no fix listed |
Affected products
- arasatasaygin is.js
Classification
References
-
securitylab.github.com
/advisories/GHSL-2020-295-redos-is.js
advisory, exploit, third-party-advisory
-
github.com
/arasatasaygin/is.js/issues/320
web, issue-tracking, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2020-26302
advisory
-
github.com
/arasatasaygin/is.js
package
Sources
- CVE List CVE-2020-26302
- GitHub Advisory GHSA-pvrw-g6fx-mcx2
- NVD CVE-2020-26302
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