CVE-2005-2661: Format string vulnerability in the ParseBannerAndCapability function in main.c for up-imapproxy 1.2.3 and 1.2.

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HIGH 7.5WATCHLISTDOWNGRADE

CVE-2005-2661 is a high-severity flaw (CVSS 7.5) affecting up-imapproxy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Format string vulnerability in the ParseBannerAndCapability function in main.c for up-imapproxy 1.2.3 and 1.2.4 allows remote IMAP servers to execute arbitrary code via format string specifiers in a banner or capability line.

Why this priority

High severity
EPSS top 4%: very likely to be exploited
Public exploit reference
On your watchlist

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	12.1% (top 4%)
CISA exploited list	No
Published	2005-10-14
Last modified	2026-06-16

Publisher (CNA): Debian GNU/Linux · Vendor: up-imapproxy

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

Am I affected?

Timeline

2005-10-14 10:02 UTCPublished CVE record published
2026-06-16 22:15 UTCUpdated Record last modified

up-imapproxy up-imapproxy DOWNGRADE

Affected: 1.2.3 · 1.2.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.2.3

1. Check installed version

apt-cache policy up-imapproxy || rpm -q up-imapproxy || up-imapproxy --version

2. No fixed release: DOWNGRADE to a release before 1.2.3 (Debian / Ubuntu)

apt-cache madison up-imapproxy sudo apt install up-imapproxy=<VERSION_BEFORE_1.2.3> sudo apt-mark hold up-imapproxy

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

dnf --showduplicates list up-imapproxy sudo dnf downgrade up-imapproxy-<VERSION_BEFORE_1.2.3> sudo dnf versionlock add up-imapproxy

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.

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: Up-IMAPProxy 1.2.3/1.2.4 - Multiple Unspecified Remote Format String Vulnerabilities

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-2005-2661?

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

Is CVE-2005-2661 being exploited?

CVE-2005-2661 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-2005-2661 affect?

CVE-2005-2661 affects up-imapproxy. Severity is high (CVSS 7.5). Format string vulnerability in the ParseBannerAndCapability function in main.c for up-imapproxy 1.2.3 and 1.2.4 allows remote IMAP servers to execute arbitrary code via format string specifiers in a banner or capability line.

How urgent is CVE-2005-2661?

Priority 60/100. High severity; EPSS top 4%: very likely to be exploited; Public exploit reference; On your watchlist

References

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