CVE-2017-17689: The S/MIME specification allows a Cipher Block Chaining (CBC) malleability-gadget attack that can indirectly l

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MEDIUM 5.9REMOTEMITIGATEMITIGATEMITIGATE

CVE-2017-17689 is a medium-severity flaw (CVSS 5.9) affecting nine, mail, mail. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The S/MIME specification allows a Cipher Block Chaining (CBC) malleability-gadget attack that can indirectly lead to plaintext exfiltration, aka EFAIL.

Why this priority

EPSS top 9%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	4.1% (top 9%)
CISA exploited list	No
Published	2018-05-16
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: 9folders · apple · bloop · emclient · flipdogsolutions

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

Am I affected?

Timeline

2018-05-16 19:29 UTCPublished CVE record published
2026-06-17 01:11 UTCUpdated Record last modified

9folders nine MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

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

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

apple mail MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

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

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

apple mail MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

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

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

bloop airmail MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

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

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

emclient emclient MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

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

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

flipdogsolutions maildroid MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

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

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

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-2017-17689?

nine: mitigate or apply the listed mitigation; mail: mitigate or apply the listed mitigation; mail: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2017-17689 being exploited?

CVE-2017-17689 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-2017-17689 affect?

CVE-2017-17689 affects nine, mail, mail. Severity is medium (CVSS 5.9). The S/MIME specification allows a Cipher Block Chaining (CBC) malleability-gadget attack that can indirectly lead to plaintext exfiltration, aka EFAIL.

How urgent is CVE-2017-17689?

Priority 53/100. EPSS top 9%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

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References

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