7.5

CVE-2021-42697: akka http_server Uncontrolled Recursion

CVSS: 7.5v3.1HighModified
AliasesGHSA-3hw2-h67c-wq66
Published 02-11-2021Last modified 04-08-2024
Open JSON

Vulnerability summary

CVE-2021-42697 is a high (CVSS 7.5) Uncontrolled Recursion vulnerability in akka http_server. EPSS estimates a 36.14% chance of exploitation in the next 30 days, higher than 98.4% of scored vulnerabilities. 2 public exploits are recorded.

Overall risk
47/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
36.14%
0%100%
High · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits2reference, exploit-database

Timeline

  1. 02-11-2021
    PublishedVulnerability first disclosed.
  2. 04-08-2024
    Last modifiedVulnerability information updated.

Description

Akka HTTP 10.1.x before 10.1.15 and 10.2.x before 10.2.7 can encounter stack exhaustion while parsing HTTP headers, which allows a remote attacker to conduct a Denial of Service attack by sending a User-Agent header with deeply nested comments.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

36.14%

Chance of exploitation in the next 30 days

Percentile

98%

Versus all other CVEs

30-day change

0.00 pp

From 36.14% on 21-09-2026

21-09-202621-10-2026
EPSS score
36.14%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

2 found
  • referenceUnverified

    Exploit Reference (packetstormsecurity.com)

    Maturity: unknown

  • exploit-databaseremotemultipleUnverified

    Akka HTTP 10.1.14 - Denial of Service

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Com.typesafe.akka7 products
  • aakka-http-core_2.13.0-M3≥ 10.1.0 (No fix recorded)
  • akka-http-core_2.11≥ 10.1.0, < 10.1.15
  • akka-http-core_2.12≥ 10.1.0, < 10.1.15 | ≥ 10.2.0-M1, < 10.2.7
  • akka-http-core_2.13≥ 10.1.0, < 10.1.15 | ≥ 10.2.0-M1, < 10.2.7
  • akka-http-core_2.13.0-M5≥ 10.1.0 (No fix recorded)
Akka1 product
  • http_server≥ 10.1.0, < 10.1.15 | ≥ 10.2.0, < 10.2.7

2 vendors · 8 products

References

9 links