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CVE-2017-17688

24
FAUCET Score

CVE-2017-17688, also known as EFAIL, describes a Cipher Feedback Mode (CFB) malleability-gadget attack within the OpenPGP specification that can indirectly lead to plaintext exfiltration. This vulnerability primarily affects applications that mishandle the Modification Detection Code (MDC) feature or accept obsolete packet types, impacting products from vendors such as Apple, Mozilla, and Microsoft. The attack has a medium severity CVSS score of 5.9, indicating a network-based attack with high complexity and potential for high confidentiality impact, but no integrity or availability impact. There is no evidence of active exploitation, and no public exploit code (Metasploit, Nuclei, ExploitDB) is available, though it has received some community and media attention.

Impacted Technologies

VendorProductVersion(s)CPE
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:apple:mail:-:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:apple:mail:-:*:*:*:*:iphone_os:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:bloop:airmail:-:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:emclient:emclient:-:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:flipdogsolutions:maildroid:-:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

5.9MEDIUM

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
3.6
CvssVersion
3.0

Exploit Intelligence

EPSS Score
5.50%
Probability of exploitation in next 30 days
EPSS Percentile
92.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-24
Model: v2026.06.15
This CVE's current EPSS score of 0.0550 is in the 90th percentile among its peer group of 19,953 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Advisories (1)

redhatCVE-2017-17688Moderate

OpenPGP: CFB gadget attacks allows to exfiltrate plaintext out of encrypted emails

May 14, 2018

References

flaked.sockpuppet.org / 2018/05/16/a-unified-timeline.html
Third Party Advisory
efail.de
ExploitMitigationThird Party Advisory
lists.gnupg.org / pipermail/gnupg-users/2018-May/060334.html
Third Party Advisory
news.ycombinator.com / item
Issue TrackingThird Party Advisory
protonmail.com / blog/pgp-vulnerability-efail
Issue TrackingThird Party Advisory
twitter.com / matthew_d_green/status/995996706457243648
Third Party Advisory
patreon.com / posts/cybersecurity-15-18814817
Issue TrackingThird Party Advisory
synology.com / support/security/Synology_SA_18_22
Third Party Advisory
securityfocus.com / bid/104162
Third Party AdvisoryVDB Entry
securitytracker.com / id/1040904
Third Party AdvisoryVDB Entry