CVE-2007-3153: The ares_init:randomize_key function in c-ares, on platforms other than Windows, uses a weak facility for prod

Routine

MEDIUM 5.0DOWNGRADE

CVE-2007-3153 is a medium-severity flaw (CVSS 5.0) affecting c-ares. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The ares_init:randomize_key function in c-ares, on platforms other than Windows, uses a weak facility for producing a random number sequence (Unix rand), which makes it easier for remote attackers to spoof DNS responses by guessing certain values.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	1.2% (top 32%)
CISA exploited list	No
Published	2007-06-11
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: daniel stenberg

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

Am I affected?

Timeline

2007-06-11 22:30 UTCPublished CVE record published
2026-06-16 22:41 UTCUpdated Record last modified

daniel stenberg c-ares DOWNGRADE

Affected: 1.0 · 1.1 · 1.2 · 1.2.1 · 1.3 · 1.3.1 · 1.3.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

apt-cache policy c-ares || rpm -q c-ares || c-ares --version

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison c-ares sudo apt install c-ares=<VERSION_BEFORE_1.0> sudo apt-mark hold c-ares

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list c-ares sudo dnf downgrade c-ares-<VERSION_BEFORE_1.0> sudo dnf versionlock add c-ares

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-2007-3153?

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

Is CVE-2007-3153 being exploited?

CVE-2007-3153 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-2007-3153 affect?

CVE-2007-3153 affects c-ares. Severity is medium (CVSS 5.0). The ares_init:randomize_key function in c-ares, on platforms other than Windows, uses a weak facility for producing a random number sequence (Unix rand), which makes it easier for remote attackers to spoof DNS responses by guessing certain

How urgent is CVE-2007-3153?

Priority 34/100. No elevated risk signals yet.

Software pages

Windows vulnerabilities

Related CVEs

CVE-2025-62408 MEDIUM 5.9 UPGRADE c-ares is an asynchronous resolver library
CVE-2024-25629 MEDIUM 4.4 UPGRADE MITIGATE c-ares is a C library for asynchronous DNS requests
CVE-2023-32067 HIGH 7.5 UPGRADE MITIGATE c-ares is an asynchronous resolver library
CVE-2023-31147 MEDIUM 5.9 UPGRADE MITIGATE c-ares is an asynchronous resolver library
CVE-2023-31130 MEDIUM 4.1 UPGRADE MITIGATE c-ares is an asynchronous resolver library

References

← Back to latest CVEs