CVE-2015-9239: ansi2html is vulnerable to regular expression denial of service (ReDoS) when certain types of user input is pa

Q: How do I fix CVE-2015-9239?

ansi2html: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2015-9239 being exploited?

CVE-2015-9239 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2015-9239 affect?

CVE-2015-9239 affects ansi2html. Severity is high (CVSS 7.5). ansi2html is vulnerable to regular expression denial of service (ReDoS) when certain types of user input is passed in.

Q: How urgent is CVE-2015-9239?

Priority 53/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEDOWNGRADE

CVE-2015-9239 is a high-severity flaw (CVSS 7.5) affecting ansi2html. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ansi2html is vulnerable to regular expression denial of service (ReDoS) when certain types of user input is passed in.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.1% (top 34%)
CISA exploited list	No
Weakness	CWE-400, CWE-20
Published	2018-05-31
Last modified	2026-06-17

Publisher (CNA): HackerOne · Vendor: ansi2html project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-05-31 20:29 UTCPublished CVE record published
2026-06-17 00:36 UTCUpdated Record last modified

ansi2html project ansi2html DOWNGRADE

Affected: 0.0.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.0.1

1. Check installed version

npm ls ansi2html

2. No fixed release: DOWNGRADE to a release before 0.0.1

npm view ansi2html versions npm install ansi2html@"<0.0.1"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2015-9239?

ansi2html: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2015-9239 being exploited?

CVE-2015-9239 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2015-9239 affect?

CVE-2015-9239 affects ansi2html. Severity is high (CVSS 7.5). ansi2html is vulnerable to regular expression denial of service (ReDoS) when certain types of user input is passed in.

How urgent is CVE-2015-9239?

Priority 53/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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