CVE-2011-3481: The index_get_ids function in index.c in imapd in Cyrus IMAP Server before 2.4.11, when server-side threading

Q: How do I fix CVE-2011-3481?

cyrus imap server: upgrade to newer than 2.4.10. Exact commands for each OS are on this page.

Q: Is CVE-2011-3481 being exploited?

CVE-2011-3481 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-2011-3481 affect?

CVE-2011-3481 affects cyrus imap server. Severity is medium (CVSS 4.3). The index_get_ids function in index.c in imapd in Cyrus IMAP Server before 2.4.11, when server-side threading is enabled, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted Referen

Q: How urgent is CVE-2011-3481?

Priority 36/100. No elevated risk signals yet.

Routine

MEDIUM 4.3UPGRADE

CVE-2011-3481 is a medium-severity flaw (CVSS 4.3) affecting cyrus imap server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The index_get_ids function in index.c in imapd in Cyrus IMAP Server before 2.4.11, when server-side threading is enabled, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted References header in an e-mail message.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.3 (Medium)
EPSS exploit chance	2.1% (top 18%)
CISA exploited list	No
Published	2011-09-14
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: cmu

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

Am I affected?

Timeline

2011-09-14 17:17 UTCPublished CVE record published
2026-06-16 23:33 UTCUpdated Record last modified

cmu cyrus imap server UPGRADE

Affected: <= 2.4.10 · 2.0.17 · 2.1.16 · 2.1.17 · 2.1.18 · 2.2.8 · 2.2.9 · 2.2.10

Fixed in: newer than 2.4.10

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy cyrus-imap-server || rpm -q cyrus-imap-server || cyrus-imap-server --version

2. UPGRADE to newer than 2.4.10 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade cyrus-imap-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade cyrus-imap-server

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-2011-3481?

cyrus imap server: upgrade to newer than 2.4.10. Exact commands for each OS are on this page.

Is CVE-2011-3481 being exploited?

CVE-2011-3481 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-2011-3481 affect?

CVE-2011-3481 affects cyrus imap server. Severity is medium (CVSS 4.3). The index_get_ids function in index.c in imapd in Cyrus IMAP Server before 2.4.11, when server-side threading is enabled, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted Referen

How urgent is CVE-2011-3481?

Priority 36/100. No elevated risk signals yet.

Related CVEs

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CVE-2009-2632 MEDIUM 4.4 DOWNGRADE Buffer overflow in the SIEVE script component (sieve/script.c), as used in cyrus-imapd in Cyrus IMAP Server 2.
CVE-2004-1067 HIGH 10.0 DOWNGRADE MITIGATE Off-by-one error in the mysasl_canon_user function in Cyrus IMAP Server 2.2.9 and earlier leads to a buffer ov
CVE-2004-1015 HIGH 10.0 DOWNGRADE MITIGATE Buffer overflow in proxyd for Cyrus IMAP Server 2.2.9 and earlier, with the imapmagicplus option enabled, may

References

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