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CVE-2018-10903

26
FAUCET Score

CVE-2018-10903 is a high-severity vulnerability in python-cryptography versions 1.9.0 to 2.2, affecting products like Canonical and Red Hat OpenStack and Ubuntu Linux. The flaw allows an attacker to bypass the MAC check in the finalize_with_tag API with a 1 in 256 chance by crafting a shortened tag, potentially leading to key leakage. With a CVSS score of 7.5, it represents a network-exploitable vulnerability with high confidentiality impact. There is currently no public exploit code, active exploitation, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 1.9.0, < 2.3CPE matchmatch criteria
cpe:2.3:a:cryptography:python-cryptography:*:*:*:*:*:*:*:*
13CPE matchmatch criteria
cpe:2.3:a:redhat:openstack:13:*:*:*:*:*:*:*
18.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*

CVSS Data

CVSS version used by this source: 3.0

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.0

Exploit Intelligence

EPSS Score
3.20%
Probability of exploitation in next 30 days
EPSS Percentile
86.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0320 is in the 76th percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (5)

github_advisorypatch availablevia nvd_reference
View patch
pippatch availablevia ghsa
Product: cryptographyFixed in: 2.3
redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenStack Platform 13.0 (Queens)Fixed in: python-cryptography-0:2.1.4-3.el7ost
View patch
redhatno patchvia redhat_api
Product: Red Hat OpenStack Platform 14 (Rocky)Fixed in: python-cryptography

Vendor Advisories (2)

pipGHSA-fcf9-3qw3-gxmjhigh

PyCA Cryptography vulnerable to GCM tag forgery

Jul 31, 2018
redhatCVE-2018-10903Moderate

python-cryptography: GCM tag forgery via truncated tag in finalize_with_tag API

Jul 18, 2018

References

access.redhat.com / errata/RHSA-2018:3600
bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
github.com / pyca/cryptography/pull/4342/commits/688e0f673bfbf43fa898994326c6877f00ab19ef
PatchThird Party Advisory
usn.ubuntu.com / 3720-1
Third Party Advisory