CVE-2026-39410

mediumpriority · track · 0EPSS 0.003 · 25 %ileDEEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.33% (25th) EPSS
CVSS 4.8 · medium
Is it mine?
27 products
Check your exposure
Who says so?
4 sources
cnnvd · enisa_euvd · cert_bund · osv

EPSS · scored 2026-10-22

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.12, a discrepancy between browser cookie parsing and parse() handling allows cookie prefix protections to be bypassed. Cookie names that are treated as distinct by the browser may be normalized to the same key by parse(), allowing attacker-controlled cookies to override legitimate ones. This vulnerability is fixed in 4.12.12.

01

cvss

Technical severity, 0–10. One row per scoring source.

4.8
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.14.8mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:Nsecondary · ENISA EU
v3.14.8mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:Nsecondary · security-advisories@github.comexploitability 2.2 · impact 2.5
v3.14.8mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:Nsecondary · OSV
v3.14.4mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

04

affected products (27)

Products and version ranges known to be affected.

showing 20 of 27
05

advisories (2)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-1407IBM App Connect Enterprise Certified Container: Mehrere SchwachstellenDeutsch2026-05-06csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise Certified Container ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, Cross-Site-Scripting-Angriffe durchzuführen, Daten zu manipulieren, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand zu verursachen.

  • GHSA-r5rp-j6wh-rvv4Hono: Non-breaking space prefix bypass in cookie name handling in getCookie()2026-04-08ghsa · osvUS

    ## Summary A discrepancy between browser cookie parsing and `parse()` handling allows cookie prefix protections to be bypassed. Cookie names that are treated as distinct by the browser may be normalized to the same key by `parse()`, allowing attacker-controlled cookies to override legitimate ones. ## Details Browsers follow RFC 6265bis and only trim SP (`0x20`) and HTAB (`0x09`) from cookie names. Other characters, such as the non-breaking space (`U+00A0`), are preserved as part of the cookie name. For example, the browser treats the following cookies as distinct: ``` "dummy-cookie" "\u00a0dummy-cookie" ``` However, `parse()` previously used JavaScript's `trim()`, which removes a broader set of characters including `U+00A0`. As a result, both names are normalized to: ``` "dummy-cookie" ``` This mismatch allows attacker-controlled cookies with a `U+00A0` prefix to shadow or override legitimate cookies when accessed via `getCookie()`. ## Impact An attacker who can set cookies (e.g., via a man-in-the-middle on a non-secure page or other injection vector) can bypass cookie prefix protections and override sensitive cookies. This may lead to: * Bypassing `__Secure-` and `__Host-` prefix protections * Overriding cookies that rely on the Secure attribute * Session fixation or session hijacking depending on application usage This issue affects applications that rely on `getCookie()` for security-sensitive cookie handling.

06

also known as (2)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

published 2026-04-08modified 2026-07-24
08

references (10)

External citations — patches, advisories, analysis.

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