CVE-2001-1154: Cyrus 2.0.15, 2.0.16, and 1.6.24 on BSDi 4.2, with IMAP enabled, allows remote attackers to cause a denial of

Routine

MEDIUM 5.0DOWNGRADEMITIGATE

CVE-2001-1154 is a medium-severity flaw (CVSS 5.0) affecting cyrus imap server, bsd os. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cyrus 2.0.15, 2.0.16, and 1.6.24 on BSDi 4.2, with IMAP enabled, allows remote attackers to cause a denial of service (hang) using PHP IMAP clients.

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	1.6% (top 24%)
CISA exploited list	No
Published	2001-08-30
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: bsdi · carnegie mellon university

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

Am I affected?

Timeline

2001-08-30 04:00 UTCPublished CVE record published
2026-06-16 21:55 UTCUpdated Record last modified

carnegie mellon university cyrus imap server DOWNGRADE

Affected: 1.6.24 · 2.0.15 · 2.0.16

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.6.24

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.6.24 (Debian / Ubuntu)

apt-cache madison cyrus-imap-server sudo apt install cyrus-imap-server=<VERSION_BEFORE_1.6.24> sudo apt-mark hold cyrus-imap-server

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

dnf --showduplicates list cyrus-imap-server sudo dnf downgrade cyrus-imap-server-<VERSION_BEFORE_1.6.24> sudo dnf versionlock add cyrus-imap-server

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.

bsdi bsd os MITIGATE

Affected: 4.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.2

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2001-1154?

cyrus imap server: downgrade or apply the listed mitigation; bsd os: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2001-1154 being exploited?

CVE-2001-1154 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-2001-1154 affect?

CVE-2001-1154 affects cyrus imap server, bsd os. Severity is medium (CVSS 5.0). Cyrus 2.0.15, 2.0.16, and 1.6.24 on BSDi 4.2, with IMAP enabled, allows remote attackers to cause a denial of service (hang) using PHP IMAP clients.

How urgent is CVE-2001-1154?

Priority 36/100. No elevated risk signals yet.

Software pages

PHP vulnerabilities

Related CVEs

CVE-2011-3481 MEDIUM 4.3 UPGRADE The index_get_ids function in index.c in imapd in Cyrus IMAP Server before 2.4.11, when server-side threading
CVE-2011-3208 HIGH 7.5 UPGRADE Stack-based buffer overflow in the split_wildmats function in nntpd.c in nntpd in Cyrus IMAP Server before 2.3
CVE-2011-1926 MEDIUM 5.1 UPGRADE The STARTTLS implementation in Cyrus IMAP Server before 2.4.7 does not properly restrict I/O buffering, which
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

References

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