CVE-2026-75922

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 82% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cisa-adp, epss
Trending — 5 sources updated this week
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line.

PSGI hands PATH_INFO to an application percent-decoded, so a %XX sequence in the client URL has become a raw byte by the time the proxy sees it. The proxy appends that byte string to the upstream base URL, and for an Upgrade tunnel writes it into a request line it serializes itself, re-encoding nothing in either path. The HTTP client that sends the resulting URL does not validate the target either. A path containing %0d%0a therefore arrives at the upstream as a CRLF that ends the request line, and a decoded space, '?' or '#' truncates it the same way.

Everything the client writes after the CRLF is read by the upstream as a second request. On the buffered path it arrives on a keep-alive connection the proxy pools and reuses for other clients. Its method, path and headers are all chosen by the client, and the upstream attributes it to the proxy, so it reaches upstream paths that the proxy's own routing does not expose.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity53% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
18%
KEV
Not listed

Published

August 23, 2026

Last Modified

August 25, 2026

Advisory Details (4)

Auto-updated Aug 25, 2026
No patch confirmed yet.
generic

Client Challenge

https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/changes
generic

Client Challenge

https://metacpan.org/release/LNATION/Reverse-Proxy-0.04/source/Proxy.xs#L400-426
generic

Client Challenge

https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L654-666
generic

Client Challenge

https://metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs#L386-399

Vendor Advisories for CVE-2026-75922(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 11× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-25 20:36 UTCGHSA enrichment
  2. 2026-08-25 19:35 UTCEG score recompute▲ 5.30
  3. 2026-08-25 19:35 UTCGHSA enrichment
  4. 2026-08-25 19:34 UTCMITRE cvelistV5CVSS v3 → 5.3 · severity → MEDIUM
  5. 2026-08-25 13:49 UTCEPSS rescore
  6. 2026-08-24 14:18 UTCEPSS rescore
  7. 2026-08-23 21:27 UTCNVD update
  8. 2026-08-23 21:15 UTCMITRE cvelistV5
  9. 2026-08-23 19:22 UTCNVD update
  10. 2026-08-23 18:31 UTCEG score recompute
  11. 2026-08-23 18:30 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-75922?
CVE-2026-75922 is a medium vulnerability published on August 23, 2026. Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line. PSGI hands PATH_INFO to an application percent-decoded, so a %XX sequence in the client URL has become a raw byte by the time the proxy sees it.…
When was CVE-2026-75922 disclosed?
CVE-2026-75922 was first published in the National Vulnerability Database on August 23, 2026, with the most recent update on August 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-75922 actively exploited?
CVE-2026-75922 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 82.4% of all scored CVEs.
What is the CVSS score of CVE-2026-75922?
CVE-2026-75922 has a CVSS v3.1 base score of 5.3 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-75922?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-75922, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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