CVE-2017-15705: A denial of service vulnerability was identified that exists in Apache SpamAssassin before 3.4.2

Q: How do I fix CVE-2017-15705?

spamassassin: upgrade to 3.4.2; ubuntu linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2017-15705 being exploited?

CVE-2017-15705 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-2017-15705 affect?

CVE-2017-15705 affects spamassassin, ubuntu linux, debian linux. Severity is medium (CVSS 5.3). A denial of service vulnerability was identified that exists in Apache SpamAssassin before 3.4.2. The vulnerability arises with certain unclosed tags in emails that cause markup to be handled incorrectly leading to scan timeouts. In Apache

Q: How urgent is CVE-2017-15705?

Priority 52/100. EPSS top 5%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

This month

MEDIUM 5.3REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2017-15705 is a medium-severity flaw (CVSS 5.3) affecting spamassassin, ubuntu linux, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A denial of service vulnerability was identified that exists in Apache SpamAssassin before 3.4.2. The vulnerability arises with certain unclosed tags in emails that cause markup to be handled incorrectly leading to scan timeouts. In Apache SpamAssassin, using HTML::Parser, we setup an object and hook into the begin and end tag event handlers In both cases, the "open" event is immediately followed by a "close" event - even if the tag *does not* cl

Why this priority

EPSS top 5%: very likely to be exploited
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	7.9% (top 5%)
CISA exploited list	No
Weakness	CWE-20
Published	2018-09-17
Last modified	2026-06-17

Publisher (CNA): Apache Software Foundation · Vendor: apache · canonical · debian · redhat

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-09-17 14:29 UTCPublished CVE record published
2026-06-17 01:08 UTCUpdated Record last modified

apache spamassassin UPGRADE

Affected: < 3.4.2

Fixed in: 3.4.2

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 3.4.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade spamassassin

Note

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

canonical ubuntu linux MITIGATE

Affected: 12.04 · 14.04 · 16.04 · 18.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 12.04

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.

debian debian linux MITIGATE

Affected: 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

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.

redhat enterprise linux desktop MITIGATE

Affected: 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

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.

redhat enterprise linux eus MITIGATE

Affected: 7.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.5

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.

redhat enterprise linux server MITIGATE

Affected: 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

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-2017-15705?

spamassassin: upgrade to 3.4.2; ubuntu linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2017-15705 being exploited?

CVE-2017-15705 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-2017-15705 affect?

CVE-2017-15705 affects spamassassin, ubuntu linux, debian linux. Severity is medium (CVSS 5.3). A denial of service vulnerability was identified that exists in Apache SpamAssassin before 3.4.2. The vulnerability arises with certain unclosed tags in emails that cause markup to be handled incorrectly leading to scan timeouts. In Apache

How urgent is CVE-2017-15705?

Priority 52/100. EPSS top 5%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities

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References

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