CURL-CVE-2026-6253

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Source
https://curl.se/docs/CVE-2026-6253.html
Import Source
https://curl.se/docs/CURL-CVE-2026-6253.json
JSON Data
https://api.test.osv.dev/v1/vulns/CURL-CVE-2026-6253
Aliases
Published
2026-04-29T08:00:00Z
Modified
2026-05-21T06:00:06.392143757Z
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:

  1. curl is setup to use specific different proxies for different URL schemes
  2. the first proxy needs credentials
  3. the second proxy uses no credentials
  4. while using the first proxy (using say http://), curl is asked to follow a redirect to a URL using another scheme (say https://), accessed using a second, different, proxy
Database specific 
{
    "www": "https://curl.se/docs/CVE-2026-6253.html",
    "affects": "both",
    "severity": "Medium",
    "CWE": {
        "id": "CWE-522",
        "desc": "Insufficiently Protected Credentials"
    },
    "last_affected": "8.19.0",
    "package": "curl",
    "URL": "https://curl.se/docs/CVE-2026-6253.json",
    "issue": "https://hackerone.com/reports/3669637"
}
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
Introduced
7.14.1
Fixed
8.20.0
Type
GIT
Repo
https://github.com/curl/curl.git
Events
Introduced
3b60bb725913ce7339aefef0a14b12df4c24db60
Fixed
188c2f166a20fa97c2325b2da7d0e5cecc13725f

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
Other
curl-7_14_1
curl-7_15_0
curl-7_15_1
curl-7_15_2
curl-7_15_3
curl-7_15_4
curl-7_15_5
curl-7_15_6-prepipeline
curl-7_16_0
curl-7_16_1
curl-7_16_2
curl-7_16_3
curl-7_16_4
curl-7_17_0
curl-7_17_0-preldapfix
curl-7_17_1
curl-7_18_0
curl-7_18_1
curl-7_18_2
curl-7_19_0
curl-7_19_1
curl-7_19_2
curl-7_19_3
curl-7_19_4
curl-7_19_5
curl-7_19_6
curl-7_19_7
curl-7_20_0
curl-7_20_1
curl-7_21_0
curl-7_21_1
curl-7_21_2
curl-7_21_3
curl-7_21_4
curl-7_21_5
curl-7_21_6
curl-7_21_7
curl-7_22_0
curl-7_23_0
curl-7_23_1
curl-7_24_0
curl-7_25_0
curl-7_26_0
curl-7_27_0
curl-7_28_0
curl-7_28_1
curl-7_29_0
curl-7_30_0
curl-7_31_0
curl-7_32_0
curl-7_33_0
curl-7_34_0
curl-7_35_0
curl-7_36_0
curl-7_37_0
curl-7_37_1
curl-7_38_0
curl-7_39_0
curl-7_40_0
curl-7_41_0
curl-7_42_0
curl-7_42_1
curl-7_43_0
curl-7_44_0
curl-7_45_0
curl-7_46_0
curl-7_47_0
curl-7_47_1
curl-7_48_0
curl-7_49_0
curl-7_49_1
curl-7_50_0
curl-7_50_1
curl-7_50_2
curl-7_50_3
curl-7_51_0
curl-7_52_0
curl-7_52_1
curl-7_53_0
curl-7_53_1
curl-7_54_0
curl-7_54_1
curl-7_55_0
curl-7_55_1
curl-7_56_0
curl-7_56_1
curl-7_57_0
curl-7_58_0
curl-7_59_0
curl-7_60_0
curl-7_61_0
curl-7_61_1
curl-7_62_0
curl-7_63_0
curl-7_64_0
curl-7_64_1
curl-7_65_0
curl-7_65_1
curl-7_65_2
curl-7_65_3
curl-7_66_0
curl-7_67_0
curl-7_68_0
curl-7_69_0
curl-7_69_1
curl-7_70_0
curl-7_71_0
curl-7_71_1
curl-7_72_0
curl-7_73_0
curl-7_74_0
curl-7_75_0
curl-7_76_0
curl-7_76_1
curl-7_77_0
curl-7_78_0
curl-7_79_0
curl-7_79_1
curl-7_80_0
curl-7_81_0
curl-7_82_0
curl-7_83_0
curl-7_83_1
curl-7_84_0
curl-7_85_0
curl-7_86_0
curl-7_87_0
curl-7_88_0
curl-7_88_1
curl-8_0_0
curl-8_0_1
curl-8_10_0
curl-8_10_1
curl-8_11_0
curl-8_11_1
curl-8_12_0
curl-8_12_1
curl-8_13_0
curl-8_14_0
curl-8_14_1
curl-8_15_0
curl-8_16_0
curl-8_17_0
curl-8_18_0
curl-8_19_0
curl-8_1_0
curl-8_1_1
curl-8_1_2
curl-8_2_0
curl-8_2_1
curl-8_3_0
curl-8_4_0
curl-8_5_0
curl-8_6_0
curl-8_7_0
curl-8_7_1
curl-8_8_0
curl-8_9_0
curl-8_9_1
rc-8_18_0-1
rc-8_18_0-2
rc-8_18_0-3
rc-8_19_0-1
rc-8_19_0-2
rc-8_19_0-3
rc-8_20_0-1
rc-8_20_0-2
tiny-curl-7_72_0
tiny-curl-8_4_0

Database specific

source 
"https://curl.se/docs/CURL-CVE-2026-6253.json"