CVE-2011-1924: Buffer overflow in the policy_summarize function in or/policies.c in Tor before 0.2.1.30 allows remote attacke

Q: How do I fix CVE-2011-1924?

tor: upgrade to newer than 0.2.1.29. Exact commands for each OS are on this page.

Q: Is CVE-2011-1924 being exploited?

CVE-2011-1924 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-2011-1924 affect?

CVE-2011-1924 affects tor. Severity is medium (CVSS 5.0). Buffer overflow in the policy_summarize function in or/policies.c in Tor before 0.2.1.30 allows remote attackers to cause a denial of service (directory authority crash) via a crafted policy that triggers creation of a long port list.

Q: How urgent is CVE-2011-1924?

Priority 39/100. No elevated risk signals yet.

Routine

MEDIUM 5.0UPGRADE

CVE-2011-1924 is a medium-severity flaw (CVSS 5.0) affecting tor. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in the policy_summarize function in or/policies.c in Tor before 0.2.1.30 allows remote attackers to cause a denial of service (directory authority crash) via a crafted policy that triggers creation of a long port list.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	2.8% (top 13%)
CISA exploited list	No
Weakness	CWE-119
Published	2011-06-14
Last modified	2026-06-16

Publisher (CNA): Red Hat, Inc. · Vendor: tor

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

Am I affected?

Timeline

2011-06-14 17:55 UTCPublished CVE record published
2026-06-16 23:30 UTCUpdated Record last modified

tor tor UPGRADE

Affected: <= 0.2.1.29 · 0.0.2 · 0.0.2_pre13 · 0.0.2_pre14 · 0.0.2_pre15 · 0.0.2_pre16 · 0.0.2_pre17 · 0.0.2_pre18

Fixed in: newer than 0.2.1.29

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 0.2.1.29 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tor

Note

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

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-2011-1924?

tor: upgrade to newer than 0.2.1.29. Exact commands for each OS are on this page.

Is CVE-2011-1924 being exploited?

CVE-2011-1924 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-2011-1924 affect?

CVE-2011-1924 affects tor. Severity is medium (CVSS 5.0). Buffer overflow in the policy_summarize function in or/policies.c in Tor before 0.2.1.30 allows remote attackers to cause a denial of service (directory authority crash) via a crafted policy that triggers creation of a long port list.

How urgent is CVE-2011-1924?

Priority 39/100. No elevated risk signals yet.

Related CVEs

CVE-2026-44603 LOW 3.7 UPGRADE Tor before 0.4.9.7 has an out-of-bounds read by one byte via a malformed BEGIN cell, aka TROVE-2026-007.
CVE-2026-44597 LOW 3.7 UPGRADE Tor before 0.4.9.7 has an out-of-bounds read when an END, a TRUNCATE, or a TRUNCATED cell lacks a reason in it
CVE-2026-44600 LOW 3.7 UPGRADE Tor before 0.4.9.7 mishandles accounting of the conflux out-of-order queue during the clearing of a queue, aka
CVE-2026-44601 LOW 3.7 UPGRADE Tor before 0.4.9.7, when circuit queue memory pressure exists, can experience a client crash because of a doub
CVE-2026-44602 LOW 3.7 UPGRADE Tor before 0.4.9.7 has a NULL pointer dereference when a CERT cell is received out of order, aka TROVE-2026-00

References

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