How severe is CVE-2026-33129?

CVE-2026-33129 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-33129 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33129?

CVE-2026-33129 primarily affects H3. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-33129?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-33129 have an EU (EUVD) identifier?

Yes. CVE-2026-33129 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13668.

When was CVE-2026-33129 published?

CVE-2026-33129 was published on 2026-03-20 and last updated on 2026-06-17.

CVE-2026-33129

CVE-2026-33129 is a medium-severity vulnerability in H3 with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-208.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-13668
Weakness: CWE-208
Affected product: H3
Published: 2026-03-20
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-33129?: 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.
How severe is CVE-2026-33129?: CVE-2026-33129 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-33129 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33129?: CVE-2026-33129 primarily affects H3. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-33129?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-33129 have an EU (EUVD) identifier?: Yes. CVE-2026-33129 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13668.
When was CVE-2026-33129 published?: CVE-2026-33129 was published on 2026-03-20 and last updated on 2026-06-17.

References

Affected products (9)

cpe:2.3:a:h3:h3:2.0.0:*:*:*:*:node.js:*:*
cpe:2.3:a:h3:h3:2.0.1:rc1:*:*:*:node.js:*:*
cpe:2.3:a:h3:h3:2.0.1:rc2:*:*:*:node.js:*:*
cpe:2.3:a:h3:h3:2.0.1:rc3:*:*:*:node.js:*:*
cpe:2.3:a:h3:h3:2.0.1:rc4:*:*:*:node.js:*:*
cpe:2.3:a:h3:h3:2.0.1:rc5:*:*:*:node.js:*:*
cpe:2.3:a:h3:h3:2.0.1:rc6:*:*:*:node.js:*:*
cpe:2.3:a:h3:h3:2.0.1:rc7:*:*:*:node.js:*:*
cpe:2.3:a:h3:h3:2.0.1:rc8:*:*:*:node.js:*:*

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