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

CVE-2017-15705 is fixed in 3 products on 1 platform, first by sa-compile 3.4.2-0ubuntu0.18.04.1, released September 16, 2018. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2017-15705
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0788
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 16, 2018

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | sa-compile Ubuntu 18.04.6 LTS (bionic) | 3.4.2-0ubuntu0.18.04.1 | [sa-compile 3.4.2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-sa-compile-3.4.2-0ubuntu0.18.04.1.md) | Sep 16, 2018 |
| Linux | spamassassin Ubuntu 18.04.6 LTS (bionic) | 3.4.2-0ubuntu0.18.04.1 | [spamassassin 3.4.2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-spamassassin-3.4.2-0ubuntu0.18.04.1.md) | Sep 16, 2018 |
| Linux | spamc Ubuntu 18.04.6 LTS (bionic) | 3.4.2-0ubuntu0.18.04.1 | [spamc 3.4.2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-spamc-3.4.2-0ubuntu0.18.04.1.md) | Sep 16, 2018 |

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Data as of 2026-11-07T06:34:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo