CVE-2024-6874: macidn punycode buffer overread
Vulnerability summary
CVE-2024-6874 is a medium (CVSS 4.3) Out-of-bounds Read vulnerability in curl. EPSS estimates a 0.79% chance of exploitation in the next 30 days, higher than 56.1% of scored vulnerabilities. 1 public exploit is recorded.
Not severe (CVSS 3.1, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 2 · Related 2Timeline
- 24-07-2024PublishedVulnerability first disclosed.
- 13-02-2025Last modifiedVulnerability information updated.
Description
libcurl's URL API function [curl_url_get()](https://curl.se/libcurl/c/curl_url_get.html) offers punycode conversions, to and from IDN. Asking to convert a name that is exactly 256 bytes, libcurl ends up reading outside of a stack based buffer when built to use the *macidn* IDN backend. The conversion function then fills up the provided buffer exactly - but does not null terminate the string. This flaw can lead to stack contents accidently getting returned as part of the converted string.
CVSS metrics
4 scores · 4 sources · 1 version- CVE.orgCNA3.1LowCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:NDiffers
- OSV · AlpineEcosystem advisory · calculated4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- OSV · DebianEcosystem advisory · calculated4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
EPSS trend
Probability
0.79%
Chance of exploitation in the next 30 days
Percentile
56%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.79% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundExploit Reference (hackerone.com)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Alpine1 product
- curl< 8.9.0-r0
Curl1 product
- curl8.8.0
Debian1 product
- curl< 8.9.0-1
Haxx1 product
- libcurl8.8.0
4 vendors · 4 products
References
8 links- curl.se/docs/CVE-2024-6874.jsonVendor Advisory
- curl.se/docs/CVE-2024-6874.htmlVendor Advisory
