CVE-2026-117656

Unverified Sign in with Apple callback parameter can override verified ID token claims

CVSS score

9.3

EPSS probability

—

Risk score

0.9

Published

1 h ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

Impact on My Inventory

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Vulnerability description

DayBreach AI Explanation

Verified against sources

CVE-2026-117656: pow-auth Assent Unverified Apple Callback Parameter Vulnerability

Sources read

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

A critical vulnerability in the Sign in with Apple strategy of the pow-auth Assent library allows unverified callback parameters to override verified ID token claims.

Why does it matter?

A remote attacker can impersonate another user by modifying the user parameter in the authorization callback, leading to potential account compromise in affected applications.

What should be done?

Follow the vendor advisory to update to the patched version
Review the provided commit references for fixes

Chain of evidence and sources2 verified claims

pow-auth Assent içinde assent: 0.1.25'ten 0.3.2'ye kadar olan sürümler bu güvenlik açığından etkilenmektedir.

S0 · daybreach-canonical S1 · cvelist

Doğrulanmamış kullanıcı haritası, doğrulanmış ID belirteci iddialarının üzerine yazılarak geçersiz kılınmaktadır.

S0 · daybreach-canonical S1 · cvelist

Show the technical text from the sources

Acceptance of Extraneous Untrusted Data With Trusted Data vulnerability in the Sign in with Apple strategy in pow-auth Assent allows an unauthenticated remote attacker to impersonate another user via the user parameter of the authorization callback. Apple posts the user's name to the callback endpoint in a user form parameter that the browser submits and the client controls. Assent.Strategy.Apple.callback/2 in lib/assent/strategies/apple.ex decodes that parameter, and fetch_user/2 merges it over the claims of the verified ID token, so the unverified map wins. An attacker who completes a Sign in with Apple login with their own Apple ID and edits the user parameter can replace sub, email, and any other claim. Applications that look up, link, or authorize accounts by the returned subject or email then act on the attacker's values. This issue affects assent: from 0.1.25 before 0.3.2.

CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CWE: CWE-290, CWE-349

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-117656 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	pow-auth	assent	View
2	pow-auth	assent	View

Total affected vendors: 1|Products: 2

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
9.3	CVSS V40	CRITICAL	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD
9.3	CVSS V4_0	CRITICAL	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N	CVE CNA

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

cvelist

Fix commit 18898bd in pow-auth/assent

Open source

reference

Fix commit 18898bd in pow-auth/assent

Open source

Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Apply the official update named in the evidence only to the matching product and version.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-117656 is associated with the following CWEs:

CWE-290: Common Weakness Enumeration Entry CWE-290 CWE-349: Common Weakness Enumeration Entry CWE-349

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-117656 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsGerekmiyor

UserGerekmiyor

Official Sources and Advisories

Unverified Sign in with Apple callback parameter can override verified ID token claimsvendor-advisory EEF CNA record for CVE-2026-117656vendor-advisory OSV record EEF-CVE-2026-117656vendor-advisory Introducing commit a2d331e in pow-auth/assentvendor-advisory Fix commit 18898bd in pow-auth/assentpatch

CVSS Vector Radar Chart

9.3 / 10

Vulnerability Scoring Details

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone required

User InteractionNone required

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)None

Availability (Erişilebilirlik)None

Yama doğrulandı

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

pow-auth

Weakness Type (CWE & CAPEC)

CWE-290 CWE-349

Get this vulnerability through the API

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