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Vulnerability details: VCID-hsyh-djpj-9bb6
Vulnerability ID VCID-hsyh-djpj-9bb6
Aliases CVE-2026-40490
GHSA-cmxv-58fp-fm3g
Summary The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. When redirect following is enabled (followRedirect(true)), versions of AsyncHttpClient prior to 3.0.9 and 2.14.5 forward Authorization and Proxy-Authorization headers along with Realm credentials to arbitrary redirect targets regardless of domain, scheme, or port changes. This leaks credentials on cross-domain redirects and HTTPS-to-HTTP downgrades. Additionally, even when stripAuthorizationOnRedirect is set to true, the Realm object containing plaintext credentials is still propagated to the redirect request, causing credential re-generation for Basic and Digest authentication schemes via NettyRequestFactory. An attacker who controls a redirect target (via open redirect, DNS rebinding, or MITM on HTTP) can capture Bearer tokens, Basic auth credentials, or any other Authorization header value. The fix in versions 3.0.9 and 2.14.5 automatically strips Authorization and Proxy-Authorization headers and clears Realm credentials whenever a redirect crosses origin boundaries (different scheme, host, or port) or downgrades from HTTPS to HTTP. For users unable to upgrade, set `(stripAuthorizationOnRedirect(true))` in the client config and avoid using Realm-based authentication with redirect following enabled. Note that `(stripAuthorizationOnRedirect(true))` alone is insufficient on versions prior to 3.0.9 and 2.14.5 because the Realm bypass still re-generates credentials. Alternatively, disable redirect following (`followRedirect(false)`) and handle redirects manually with origin validation.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (4)
System Score Found at
cvssv3 6.8 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-40490.json
epss 0.00071 https://api.first.org/data/v1/epss?cve=CVE-2026-40490
epss 0.00071 https://api.first.org/data/v1/epss?cve=CVE-2026-40490
epss 0.00071 https://api.first.org/data/v1/epss?cve=CVE-2026-40490
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-cmxv-58fp-fm3g
cvssv3.1 6.8 https://github.com/AsyncHttpClient/async-http-client
generic_textual MODERATE https://github.com/AsyncHttpClient/async-http-client
cvssv3.1 6.8 https://github.com/AsyncHttpClient/async-http-client/commit/6b2fbb7f8
generic_textual MODERATE https://github.com/AsyncHttpClient/async-http-client/commit/6b2fbb7f8
ssvc Track https://github.com/AsyncHttpClient/async-http-client/commit/6b2fbb7f8
cvssv3.1 6.8 https://github.com/AsyncHttpClient/async-http-client/commit/ae557ad35246721c09dafb2976609cd0004e78ae
generic_textual MODERATE https://github.com/AsyncHttpClient/async-http-client/commit/ae557ad35246721c09dafb2976609cd0004e78ae
ssvc Track https://github.com/AsyncHttpClient/async-http-client/commit/ae557ad35246721c09dafb2976609cd0004e78ae
cvssv3.1 6.8 https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.14.5
generic_textual MODERATE https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.14.5
ssvc Track https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.14.5
cvssv3.1 6.8 https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.9
generic_textual MODERATE https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.9
ssvc Track https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.9
cvssv3.1 6.8 https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cmxv-58fp-fm3g
cvssv3.1_qr MODERATE https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cmxv-58fp-fm3g
generic_textual MODERATE https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cmxv-58fp-fm3g
ssvc Track https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cmxv-58fp-fm3g
cvssv3.1 6.8 https://nvd.nist.gov/vuln/detail/CVE-2026-40490
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2026-40490
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-40490.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

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Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N Found at https://github.com/AsyncHttpClient/async-http-client
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N Found at https://github.com/AsyncHttpClient/async-http-client/commit/6b2fbb7f8
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

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Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-20T14:51:47Z/ Found at https://github.com/AsyncHttpClient/async-http-client/commit/6b2fbb7f8
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N Found at https://github.com/AsyncHttpClient/async-http-client/commit/ae557ad35246721c09dafb2976609cd0004e78ae
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

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Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-20T14:51:47Z/ Found at https://github.com/AsyncHttpClient/async-http-client/commit/ae557ad35246721c09dafb2976609cd0004e78ae
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N Found at https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.14.5
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

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Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-20T14:51:47Z/ Found at https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.14.5
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N Found at https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.9
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

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Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-20T14:51:47Z/ Found at https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.9
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N Found at https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cmxv-58fp-fm3g
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

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none

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unchanged

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Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-20T14:51:47Z/ Found at https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cmxv-58fp-fm3g
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2026-40490
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

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none

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unchanged

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Exploit Prediction Scoring System (EPSS)
Percentile 0.21849
EPSS Score 0.00071
Published At June 5, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-04T16:28:12.432968+00:00 Debian Importer Import https://security-tracker.debian.org/tracker/data/json 38.6.0