CURL-CVE-2026-6253
- Source
- https://curl.se/docs/CVE-2026-6253.html
- Import Source
- https://curl.se/docs/CURL-CVE-2026-6253.json
- JSON Data
- https://api.osv.dev/v1/vulns/CURL-CVE-2026-6253
- Aliases
-
- CVE-2026-6253
- Published
- 2026-04-29T08:00:00Z
- Modified
- 2026-04-29T14:02:00.606665Z
- Summary
- proxy credentials leak over redirect-to proxy
- Details
-
curl might erroneously pass on credentials for a first proxy to a second proxy.
This can happen when the following conditions are true:
- curl is setup to use specific different proxies for different URL schemes
- the first proxy needs credentials
- the second proxy uses no credentials
- while using the first proxy (using say
http://), curl is asked to follow a redirect to a URL using another scheme (sayhttps://), accessed using a second, different, proxy
- Database specific
{ "last_affected": "8.19.0", "package": "curl", "www": "https://curl.se/docs/CVE-2026-6253.html", "CWE": { "desc": "Insufficiently Protected Credentials", "id": "CWE-522" }, "severity": "Medium", "URL": "https://curl.se/docs/CVE-2026-6253.json", "issue": "https://hackerone.com/reports/3669637", "affects": "both" }- References
-
- Credits
-
-
- Dwij Mehta (O2 Lab - FINDER
-
- Texas A&M University) - FINDER
-
- Daniel Stenberg - REMEDIATION_DEVELOPER
-
Affected packages
Git / github.com/curl/curl.git
Affected ranges
- Type
- SEMVER
- Events
-
Introduced7.14.1Fixed8.20.0
- Type
- GIT
- Repo
- https://github.com/curl/curl.git
- Events
Affected versions
7.*
7.14.1
7.15.0
7.15.1
7.15.2
7.15.3
7.15.4
7.15.5
7.16.0
7.16.1
7.16.2
7.16.3
7.16.4
7.17.0
7.17.1
7.18.0
7.18.1
7.18.2
7.19.0
7.19.1
7.19.2
7.19.3
7.19.4
7.19.5
7.19.6
7.19.7
7.20.0
7.20.1
7.21.0
7.21.1
7.21.2
7.21.3
7.21.4
7.21.5
7.21.6
7.21.7
7.22.0
7.23.0
7.23.1
7.24.0
7.25.0
7.26.0
7.27.0
7.28.0
7.28.1
7.29.0
7.30.0
7.31.0
7.32.0
7.33.0
7.34.0
7.35.0
7.36.0
7.37.0
7.37.1
7.38.0
7.39.0
7.40.0
7.41.0
7.42.0
7.42.1
7.43.0
7.44.0
7.45.0
7.46.0
7.47.0
7.47.1
7.48.0
7.49.0
7.49.1
7.50.0
7.50.1
7.50.2
7.50.3
7.51.0
7.52.0
7.52.1
7.53.0
7.53.1
7.54.0
7.54.1
7.55.0
7.55.1
7.56.0
7.56.1
7.57.0
7.58.0
7.59.0
7.60.0
7.61.0
7.61.1
7.62.0
7.63.0
7.64.0
7.64.1
7.65.0
7.65.1
7.65.2
7.65.3
7.66.0
7.67.0
7.68.0
7.69.0
7.69.1
7.70.0
7.71.0
7.71.1
7.72.0
7.73.0
7.74.0
7.75.0
7.76.0
7.76.1
7.77.0
7.78.0
7.79.0
7.79.1
7.80.0
7.81.0
7.82.0
7.83.0
7.83.1
7.84.0
7.85.0
7.86.0
7.87.0
7.88.0
7.88.1
8.*
8.0.0
8.0.1
8.1.0
8.1.1
8.1.2
8.10.0
8.10.1
8.11.0
8.11.1
8.12.0
8.12.1
8.13.0
8.14.0
8.14.1
8.15.0
8.16.0
8.17.0
8.18.0
8.19.0
8.2.0
8.2.1
8.3.0
8.4.0
8.5.0
8.6.0
8.7.0
8.7.1
8.8.0
8.9.0
8.9.1
Database specific
vanir_signatures
[
{
"deprecated": false,
"signature_version": "v1",
"id": "CURL-CVE-2026-6253-567ef573",
"digest": {
"line_hashes": [
"320283323316423495706633503224444008036",
"19994496920908832416557048544266336889",
"44401832196883609822291944848878550440"
],
"threshold": 0.9
},
"source": "https://github.com/curl/curl.git/commit/188c2f166a20fa97c2325b2da7d0e5cecc13725f",
"signature_type": "Line",
"target": {
"file": "lib/transfer.h"
}
},
{
"deprecated": false,
"signature_version": "v1",
"id": "CURL-CVE-2026-6253-5d3f5454",
"digest": {
"length": 4505.0,
"function_hash": "139334896162729578171190526636779489187"
},
"source": "https://github.com/curl/curl.git/commit/188c2f166a20fa97c2325b2da7d0e5cecc13725f",
"signature_type": "Function",
"target": {
"file": "lib/http.c",
"function": "Curl_http_follow"
}
},
{
"deprecated": false,
"signature_version": "v1",
"id": "CURL-CVE-2026-6253-bc9f0c89",
"digest": {
"line_hashes": [
"301497188995651378874451872512076462662",
"39041385079473591857179953523438972240",
"245126298402424295240682723994409875436",
"130456450287203782996963805498898774537",
"252935111858746281325765865069989177309",
"134076049495414102025307212910596160676",
"325230785338800994283858617489882591598",
"38653753554547018803004112826938162208",
"44611476952592811549123439060526908855",
"157464944269042598628764936189408002298"
],
"threshold": 0.9
},
"source": "https://github.com/curl/curl.git/commit/188c2f166a20fa97c2325b2da7d0e5cecc13725f",
"signature_type": "Line",
"target": {
"file": "lib/http.c"
}
},
{
"deprecated": false,
"signature_version": "v1",
"id": "CURL-CVE-2026-6253-c7370a5b",
"digest": {
"length": 4130.0,
"function_hash": "133775919468899809857643957825120315519"
},
"source": "https://github.com/curl/curl.git/commit/188c2f166a20fa97c2325b2da7d0e5cecc13725f",
"signature_type": "Function",
"target": {
"file": "lib/transfer.c",
"function": "Curl_pretransfer"
}
},
{
"deprecated": false,
"signature_version": "v1",
"id": "CURL-CVE-2026-6253-fa1a909c",
"digest": {
"line_hashes": [
"36295398819015016879209227541784304677",
"266683780769433346767495313109351727674",
"74343392334751447410021208595166349650",
"130482168700241630832648647117633451119",
"114809573277310585393632926927784920705",
"270942409412143101369179192757363315166",
"195704874027865529455510475248740394495",
"275693969075269038114978340849837412847",
"191280208239805899929764265625365776387",
"110788235810996845325760870202305047428",
"294896778886689513652694845471325568335",
"62198230481056940651069769814147160788",
"224162197528859011857116163428871728505",
"147192993515001551007464855404487667848",
"141029581736675123157948428236698842021",
"67472426873234593071183791327597773139",
"214557824649792841848707780601016219919",
"294064844480677975858224900200820637803",
"250875592161800559633017020641282063810",
"223617891052737179828071782486658974465",
"69910255553248048971390810001521175590",
"333045019392847461740113385893762036837",
"192323697311700048717499618761821280445"
],
"threshold": 0.9
},
"source": "https://github.com/curl/curl.git/commit/188c2f166a20fa97c2325b2da7d0e5cecc13725f",
"signature_type": "Line",
"target": {
"file": "lib/transfer.c"
}
}
]
source
"https://curl.se/docs/CURL-CVE-2026-6253.json"
vanir_signatures_modified
"2026-04-29T14:02:00Z"