CVE-2004-1765: Off-by-one buffer overflow in ModSecurity (mod_security) 1.7.4 for Apache 2.x, when SecFilterScanPost is enabl

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HIGH 7.5WATCHLISTDOWNGRADE

CVE-2004-1765 is a high-severity flaw (CVSS 7.5) affecting mod security. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Off-by-one buffer overflow in ModSecurity (mod_security) 1.7.4 for Apache 2.x, when SecFilterScanPost is enabled, allows remote attackers to execute arbitrary code via crafted POST requests.

Why this priority

High severity
EPSS top 8%: very likely to be exploited
On your watchlist

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	4.7% (top 8%)
CISA exploited list	No
Published	2004-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: mod security

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

Am I affected?

Timeline

2004-12-31 05:00 UTCPublished CVE record published
2026-06-16 22:08 UTCUpdated Record last modified

mod security mod security DOWNGRADE

Affected: 1.7.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.7.4

1. Check installed version

apt-cache policy mod-security || rpm -q mod-security || mod-security --version

2. No fixed release: DOWNGRADE to a release before 1.7.4 (Debian / Ubuntu)

apt-cache madison mod-security sudo apt install mod-security=<VERSION_BEFORE_1.7.4> sudo apt-mark hold mod-security

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

dnf --showduplicates list mod-security sudo dnf downgrade mod-security-<VERSION_BEFORE_1.7.4> sudo dnf versionlock add mod-security

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-2004-1765?

mod security: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2004-1765 being exploited?

CVE-2004-1765 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-2004-1765 affect?

CVE-2004-1765 affects mod security. Severity is high (CVSS 7.5). Off-by-one buffer overflow in ModSecurity (mod_security) 1.7.4 for Apache 2.x, when SecFilterScanPost is enabled, allows remote attackers to execute arbitrary code via crafted POST requests.

How urgent is CVE-2004-1765?

Priority 54/100. High severity; EPSS top 8%: very likely to be exploited; On your watchlist

Related CVEs

CVE-2007-1359 MEDIUM 6.8 DOWNGRADE Interpretation conflict in ModSecurity (mod_security) 2.1.0 and earlier allows remote attackers to bypass requ
CVE-2003-1171 HIGH 7.5 DOWNGRADE Heap-based buffer overflow in the sec_filter_out function in mod_security 1.7RC1 through 1.7.1 in Apache 2 all

References

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