CVE-2009-4535: Mongoose 2.8.0 and earlier allows remote attackers to obtain the source code for a web page by appending a / (

Q: How do I fix CVE-2009-4535?

mongoose: upgrade to newer than 2.8.0. Exact commands for each OS are on this page.

Q: Is CVE-2009-4535 being exploited?

CVE-2009-4535 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-2009-4535 affect?

CVE-2009-4535 affects mongoose. Severity is medium (CVSS 5.0). Mongoose 2.8.0 and earlier allows remote attackers to obtain the source code for a web page by appending a / (slash) character to the URI.

Q: How urgent is CVE-2009-4535?

Priority 46/100. EPSS top 6%: very likely to be exploited; Public exploit reference

This month

MEDIUM 5.0UPGRADE

CVE-2009-4535 is a medium-severity flaw (CVSS 5.0) affecting mongoose. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Mongoose 2.8.0 and earlier allows remote attackers to obtain the source code for a web page by appending a / (slash) character to the URI.

Why this priority

EPSS top 6%: very likely to be exploited
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	6.7% (top 6%)
CISA exploited list	No
Weakness	CWE-200
Published	2009-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: valenok

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2009-12-31 19:30 UTCPublished CVE record published
2026-06-16 23:13 UTCUpdated Record last modified

valenok mongoose UPGRADE

Affected: <= 2.8.0

Fixed in: newer than 2.8.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy mongoose || rpm -q mongoose || mongoose --version

2. UPGRADE to newer than 2.8.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mongoose

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mongoose

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: Mongoose Web Server 2.8 - Source Disclosure
Exploit-DB: Mongoose Web Server 2.8 - Multiple Directory Traversals

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-2009-4535?

mongoose: upgrade to newer than 2.8.0. Exact commands for each OS are on this page.

Is CVE-2009-4535 being exploited?

CVE-2009-4535 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-2009-4535 affect?

CVE-2009-4535 affects mongoose. Severity is medium (CVSS 5.0). Mongoose 2.8.0 and earlier allows remote attackers to obtain the source code for a web page by appending a / (slash) character to the URI.

How urgent is CVE-2009-4535?

Priority 46/100. EPSS top 6%: very likely to be exploited; Public exploit reference

Related CVEs

CVE-2026-5244 HIGH 7.3 UPGRADE A vulnerability has been found in Cesanta Mongoose up to 7.20
CVE-2026-6985 MEDIUM 5.3 UPGRADE A weakness has been identified in Cesanta Mongoose up to 7.20
CVE-2026-5246 MEDIUM 5.6 UPGRADE A vulnerability was determined in Cesanta Mongoose up to 7.20
CVE-2026-5245 MEDIUM 5.6 UPGRADE A vulnerability was found in Cesanta Mongoose up to 7.20
CVE-2026-6986 LOW 3.7 UPGRADE A security vulnerability has been detected in Cesanta Mongoose up to 7.20

References

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