# CVE-2026-126934: Zipline 4.3.2 before 4.8.0 Rate Limit Bypass via Spoofed X-Forwarded-For

Status: published. Published: 2026-11-11. Updated: 2026-11-11.

Zipline 4.3.2 before 4.8.0 contains a rate limit bypass vulnerability that allows unauthenticated attackers to evade throttling by spoofing X-Forwarded-For headers when core.trustProxy is enabled. Attackers can send a different X-Forwarded-For value per request to obtain fresh rate-limit buckets, enabling unlimited guessing of login passwords, TOTP codes, and file and URL passwords.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/diced/zipline/commit/6bac7e6bb18cb37c1d09f91306c1ffbdca00097c

## Affected products and versions

- diced / zipline (diced/zipline): ≥ 4.3.2; < 4.8.0 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N; source: CNA: VulnCheck

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/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; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-348

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/diced/zipline/security/advisories/GHSA-v938-v8wg-9497 (CNA: VulnCheck; vendor-advisory)

- https://github.com/diced/zipline/commit/6bac7e6bb18cb37c1d09f91306c1ffbdca00097c (CNA: VulnCheck; patch)

- https://github.com/diced/zipline/releases/tag/v4.8.0 (CNA: VulnCheck; release-notes)

- https://github.com/diced/zipline/blob/v4.7.0/src/server/index.ts#L58-L62 (CNA: VulnCheck; technical-description)

- https://github.com/diced/zipline/blob/v4.7.0/src/server/startup/plugins.ts#L70-L73 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/zipline-4.3.2-before-4.8.0-rate-limit-bypass-via-spoofed-x-forwarded-for (CNA: VulnCheck; third-party-advisory)

- https://github.com/diced/zipline/blob/v4.7.0/src/server/index.ts#L58-L62 (disclosure@vulncheck.com)

- https://github.com/diced/zipline/blob/v4.7.0/src/server/startup/plugins.ts#L70-L73 (disclosure@vulncheck.com)

- https://github.com/diced/zipline/commit/6bac7e6bb18cb37c1d09f91306c1ffbdca00097c (disclosure@vulncheck.com)

- https://github.com/diced/zipline/releases/tag/v4.8.0 (disclosure@vulncheck.com)

- https://github.com/diced/zipline/security/advisories/GHSA-v938-v8wg-9497 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/zipline-4.3.2-before-4.8.0-rate-limit-bypass-via-spoofed-x-forwarded-for (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-126934; retrieved 2026-11-11; source updated 2026-11-11

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126934; retrieved 2026-11-12; source updated 2026-11-11

Revision: b9e1d9df1e63c04984f41b06810e39821d3b8a3948b1167325d95c374eaf86d8

Canonical: https://y2.dev/cve/CVE-2026-126934

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