A denial of service vulnerability was identified that exists in Apache SpamAssassin before 3.4.2.
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* close in the HTML being parsed. Because of this, we are missing the "text" event to deal with the object normally. This can cause carefully crafted emails that might take more scan time than expected leading to a Denial of Service. The issue is possibly a bug or design decision in HTML::Parser that specifically impacts the way Apache SpamAssassin uses the module with poorly formed html. The exploit has been seen in the wild but not believed to have been purposefully part of a Denial of Service attempt. We are concerned that there may be attempts to abuse the vulnerability in the future.
- Published
- Sep 17, 2018
- Updated
- Jun 16, 2026
- EPSS
- 7.9% · 95th percentile
- CWE
- CWE-20
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Report tools
Action score
23
Monitor
Low priority for now.
- CVSS
- 21 / 40 · 5.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 2 / 30 · 7.9%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| apache | spamassassin | cpe:2.3:a:apache:spamassassin |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| redhat | enterprise linux desktop | cpe:2.3:o:redhat:enterprise_linux_desktop |
| redhat | enterprise linux eus | cpe:2.3:o:redhat:enterprise_linux_eus |
| redhat | enterprise linux server | cpe:2.3:o:redhat:enterprise_linux_server |
| redhat | enterprise linux workstation | cpe:2.3:o:redhat:enterprise_linux_workstation |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- apache spamassassinbefore 3.4.2
- canonical ubuntu linux12.04
- canonical ubuntu linux14.04
- canonical ubuntu linux16.04
- canonical ubuntu linux18.04
- debian debian linux8.0
- redhat enterprise linux desktop7.0
- redhat enterprise linux eus7.5
- redhat enterprise linux server7.0
- redhat enterprise linux workstation7.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.
Apache Software Foundation Apache SpamAssassin
- all modern versions before 3.4.2affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | spamassassin | before 3.4.2-r0 | 3.4.2-r0 |
| Alpine:v3.8 | spamassassin | before 3.4.3-r0 | 3.4.3-r0 |
| Debian:12 | spamassassin | before 3.4.2-1 | 3.4.2-1 |
| Debian:8 | spamassassin | before 3.4.2-0+deb8u1 | 3.4.2-0+deb8u1 |
| openSUSE:Leap 15.0 | spamassassin | before 3.4.2-lp150.6.3.1 | 3.4.2-lp150.6.3.1 |
| openSUSE:Tumbleweed | spamassassin | before 3.4.6-71.3 | 3.4.6-71.3 |
| Red Hat:enterprise_linux:7::client | spamassassin | before 0:3.4.0-4.el7_5 | 0:3.4.0-4.el7_5 |
| Red Hat:enterprise_linux:7::client | spamassassin-debuginfo | before 0:3.4.0-4.el7_5 | 0:3.4.0-4.el7_5 |
| SUSE:Linux Enterprise Desktop 12 SP4 | spamassassin | before 3.4.2-44.3.1 | 3.4.2-44.3.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 | spamassassin | before 3.4.2-7.4.1 | 3.4.2-7.4.1 |
Same product
apache: all recordsOther highest-scoring records for the same primary product.
- CVE-2006-2447SpamAssassin before 3.1.3, when running with vpopmail and the paranoid (-P) switch, allows remote attackers to execute arbitrary commands vi43Plan
- CVE-2018-11780A potential Remote Code Execution bug exists with the PDFInfo plugin in Apache SpamAssassin before 3.4.2.42Plan
- CVE-2020-1946Apache SpamAssassin has an OS Command Injection vulnerability41Plan
- CVE-2020-1931A command execution issue was found in Apache SpamAssassin prior to 3.4.3.34Monitor
- CVE-2020-1930A command execution issue was found in Apache SpamAssassin prior to 3.4.3.34Monitor
- CVE-2019-12420In Apache SpamAssassin before 3.4.3, a message can be crafted in a way to use excessive resources.32Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:spamassassin | 3.4.2-r0 · Alpine:v3.10 | Package registry (OSV) |
| debian:spamassassin | 3.4.2-1 · Debian:12 | Package registry (OSV) |
| opensuse:spamassassin | 3.4.2-lp150.6.3.1 · openSUSE:Leap 15.0 | Package registry (OSV) |
| red hat:spamassassin | 0:3.4.0-4.el7_5 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:spamassassin-debuginfo | 0:3.4.0-4.el7_5 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| suse:spamassassin | 3.4.2-44.3.1 · SUSE:Linux Enterprise Desktop 12 SP4 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- low · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- Low
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- lists.opensuse.org/opensuse-security-announce/2019-08/msg00002.html
- www.securityfocus.com/bid/105347
- access.redhat.com/errata/RHSA-2018:2916
- lists.apache.org/thread.html/7f6a16bc0fd0fd5e67c7fd95bd655069a2ac7d1f88e42d3c853e601c%40%3Cannounce.apache.org%3E
- lists.debian.org/debian-lts-announce/2018/11/msg00016.html
- security.gentoo.org/glsa/201812-07
- usn.ubuntu.com/3811-1/
- usn.ubuntu.com/3811-2/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.