CVE-2026-33129 | h3 has an observable timing discrepancy in basic auth utils

Exp

H3 is a minimal H(TTP) framework. Versions 2.0.1-beta.0 through 2.0.0-rc.8 contain a Timing Side-Channel vulnerability in the requireBasicAuth function due to the use of unsafe string comparison (!==). This allows an attacker to deduce the valid password character-by-character by measuring the server's response time, effectively bypassing password complexity protections. This issue is fixed in version 2.0.1-rc.9.

Published: 2026-03-20 Last update: 2026-03-20 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-33129 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.05%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-33129

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-33129

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-01 0.03% 0.05% +0.02%
2 2026-03-20 — 0.03% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33129

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 [email protected]
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 [email protected]

Weakness enumeration for CVE-2026-33129

GitHub Security Advisory for CVE-2026-33129

GHSA-26f5-8h2x-34xh · Severity: medium · Ecosystem: npm — h3 has an observable timing discrepancy in basic auth utils

Affected software / configurations for CVE-2026-33129

Vendor Product Version Raw CPE
h3 h3 2.0.0 cpe:2.3:a:h3:h3:2.0.0:*:*:*:*:node.js:*:*
h3 h3 2.0.1 cpe:2.3:a:h3:h3:2.0.1:rc1:*:*:*:node.js:*:*
h3 h3 2.0.1 cpe:2.3:a:h3:h3:2.0.1:rc2:*:*:*:node.js:*:*
h3 h3 2.0.1 cpe:2.3:a:h3:h3:2.0.1:rc3:*:*:*:node.js:*:*
h3 h3 2.0.1 cpe:2.3:a:h3:h3:2.0.1:rc4:*:*:*:node.js:*:*
h3 h3 2.0.1 cpe:2.3:a:h3:h3:2.0.1:rc5:*:*:*:node.js:*:*
h3 h3 2.0.1 cpe:2.3:a:h3:h3:2.0.1:rc6:*:*:*:node.js:*:*
h3 h3 2.0.1 cpe:2.3:a:h3:h3:2.0.1:rc7:*:*:*:node.js:*:*
h3 h3 2.0.1 cpe:2.3:a:h3:h3:2.0.1:rc8:*:*:*:node.js:*:*

References for CVE-2026-33129

cvelogic Threat Intelligence