CVE-2017-17846: An issue was discovered in Enigmail before 1.9.9

Q: How do I fix CVE-2017-17846?

enigmail: upgrade to 1.9.9; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2017-17846 being exploited?

CVE-2017-17846 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-2017-17846 affect?

CVE-2017-17846 affects enigmail, debian linux. Severity is high (CVSS 7.5). An issue was discovered in Enigmail before 1.9.9. Regular expressions are exploitable for Denial of Service, because of attempts to match arbitrarily long strings, aka TBE-01-003.

Q: How urgent is CVE-2017-17846?

Priority 57/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2017-17846 is a high-severity flaw (CVSS 7.5) affecting enigmail, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in Enigmail before 1.9.9. Regular expressions are exploitable for Denial of Service, because of attempts to match arbitrarily long strings, aka TBE-01-003.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.2% (top 18%)
CISA exploited list	No
Weakness	CWE-20
Published	2017-12-27
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · enigmail

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

Am I affected?

Timeline

2017-12-27 17:08 UTCPublished CVE record published
2026-06-17 01:11 UTCUpdated Record last modified

enigmail enigmail UPGRADE

Affected: < 1.9.9

Fixed in: 1.9.9

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 1.9.9 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade enigmail

Note

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

debian debian linux MITIGATE

Affected: 8.0 · 9.0

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.

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-2017-17846?

enigmail: upgrade to 1.9.9; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2017-17846 being exploited?

CVE-2017-17846 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-2017-17846 affect?

CVE-2017-17846 affects enigmail, debian linux. Severity is high (CVSS 7.5). An issue was discovered in Enigmail before 1.9.9. Regular expressions are exploitable for Denial of Service, because of attempts to match arbitrarily long strings, aka TBE-01-003.

How urgent is CVE-2017-17846?

Priority 57/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

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CVE-2019-12269 HIGH 7.5 UPGRADE Enigmail before 2.0.11 allows PGP signature spoofing: for an inline PGP message, an attacker can cause the pro
CVE-2018-15586 MEDIUM 6.5 UPGRADE Enigmail before 2.0.6 is prone to to OpenPGP signatures being spoofed for arbitrary messages using a PGP/INLIN
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CVE-2017-17848 HIGH 7.5 UPGRADE MITIGATE An issue was discovered in Enigmail before 1.9.9

References

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