CVE-2026-81707

CRITICAL
Published Aug 27, 2026 Modified Aug 31, 2026 CWE-20

Description

openssl_encrypt before 1.4.9 fails to sanitize the email field of imported identity documents, allowing attackers to inject ANSI escape sequences that forge the fingerprint verification line displayed to users. Attackers can deliver a crafted identity bundle through normal contact-exchange flows or keyserver responses to manipulate terminal output and display a fraudulent fingerprint, bypassing the out-of-band verification mechanism that protects against key substitution attacks.

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CVSS v3.1 Score

9.8
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0041
Probability of exploitation
0.35%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-20 Improper Input Validation

References

Frequently Asked Questions

What is CVE-2026-81707? +
openssl_encrypt before 1.4.9 fails to sanitize the email field of imported identity documents, allowing attackers to inject ANSI escape sequences that forge the fingerprint verification line displayed to users. Attackers can deliver a crafted identity bundle through normal contact-exchange flows or keyserver responses to manipulate terminal output and display a fraudulent fingerprint, bypassing the out-of-band verification mechanism that protects against key substitution attacks. It has a CVSS v3.1 base score of 9.8 (CRITICAL).
How severe is CVE-2026-81707? +
CVE-2026-81707 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0041, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-81707? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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