CVE-2026-54770

MEDIUMPre-NVD 6.16.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 73% 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: epss, secondary
Elevated
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.1Exploit: Elevated riskExposed: 0

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

WebOb provides objects for HTTP requests and responses. Prior to 1.8.11, Response._make_location_absolute() in src/webob/response.py checks a Location value for a URI scheme or leading double slash before urllib.parse.urljoin() strips leading C0 control characters and spaces. An attacker-controlled value such as a space followed by a protocol-relative or absolute URL can therefore bypass SCHEME_RE and startswith("//") checks and be normalized to an off-host redirect. Request.relative_url() and webob.exc._HTTPMove subclasses, including HTTPFound, are also affected because they use the same unsafe URL joining behavior or bypass the earlier normalization path. An unauthenticated attacker who can influence an application's redirect target can send users to an attacker-controlled host for phishing or OAuth and SSO token theft, but exploitation requires the user to follow the redirect. This issue is fixed in version 1.8.11.

CVSS v3
6.1
EG Score
6.1(medium)
EG Risk
43(Track)
EG Risk 43/100SSVC: 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
Severity61% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
27%
KEV
Not listed

Published

August 20, 2026

Last Modified

August 25, 2026

Advisory Details (3)

Auto-updated Aug 20, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
generic

GitHub - Pylons/webob at 1.8.11 · GitHub

https://github.com/Pylons/webob/tree/1.8.11
github_commit

commit ff89560643fb (Pylons/webob)

Fix landed in Pylons/webob commit ff89560643fb — awaiting tagged release

https://github.com/Pylons/webob/commit/ff89560643fb252751b4db8806a283b5377f1f07
github Patch Available🟡 PoC Available

Open redirect in Location header normalization via leading C0 control / space characters -- third times a charm? · Advisory · Pylons/webob · GitHub

https://github.com/Pylons/webob/security/advisories/GHSA-6hx8-3wjj-gr8g

Vendor Advisories for CVE-2026-54770(1)

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

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
webob0.8 ... 1.8.9 (74 versions)1.8.11—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 19× 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. 2026-08-30 02:45 UTCEG score recompute
  2. 2026-08-30 01:22 UTCEPSS rescore
  3. 2026-08-29 01:28 UTCEG score recompute
  4. 2026-08-28 21:41 UTCEPSS rescore
  5. 2026-08-27 19:11 UTCEG score recompute
  6. 2026-08-27 14:25 UTCEPSS rescore
  7. 2026-08-26 17:53 UTCEG score recompute
  8. 2026-08-26 14:46 UTCEPSS rescore
  9. 2026-08-25 15:23 UTCEG score recompute
  10. 2026-08-25 15:16 UTCEG score recompute
  11. 2026-08-25 13:49 UTCEPSS rescore
  12. 2026-08-24 22:38 UTCEG score recompute
  13. 2026-08-23 21:22 UTCEG score recompute
  14. 2026-08-23 00:19 UTCEPSS rescore
  15. 2026-08-22 20:06 UTCEG score recompute
  16. 2026-08-21 23:49 UTCEPSS rescore
  17. 2026-08-20 17:33 UTCEG score recompute
  18. 2026-08-20 16:52 UTCEG score recompute
  19. 2026-08-20 16:51 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-54770?
CVE-2026-54770 is a medium vulnerability published on August 20, 2026. WebOb provides objects for HTTP requests and responses. Prior to 1.8.11, Response.makelocationabsolute() in src/webob/response.py checks a Location value for a URI scheme or leading double slash before urllib.parse.urljoin() strips leading C0 control characters and spaces. An attacker-controlled…
When was CVE-2026-54770 disclosed?
CVE-2026-54770 was first published in the National Vulnerability Database on August 20, 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-2026-54770 actively exploited?
CVE-2026-54770 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 73.5% of all scored CVEs.
What is the CVSS score of CVE-2026-54770?
CVE-2026-54770 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-54770?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54770, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-54770

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