5.5

CVE-2021-33642: openeuler byacc Loop with Unreachable Exit Condition

Modified
Published 20-01-2023Last modified 02-04-2025

Vulnerability summary

CVE-2021-33642 is a medium (CVSS 5.5) Loop with Unreachable Exit Condition vulnerability in openeuler byacc. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.5% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.23%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 20-01-2023
    PublishedVulnerability first disclosed.
  2. 02-04-2025
    Last modifiedVulnerability information updated.

Description

When a file is processed, an infinite loop occurs in next_inline() of the more_curly() function.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.23%

Chance of exploitation in the next 30 days

Percentile

14%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.22% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Openeuler1 product
  • byacc< 1.9.20200330 | ≥ 2.0, < 2.0.20210808

1 vendor · 1 product

References

1 links