CVE-2023-30536

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 63% 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, nvd
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 6.5Exploit: NoneExposed: 0

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

slim/psr7 is a PSR-7 implementation for use with Slim 4. In versions prior to 1.6.1 an attacker could sneak in a newline (\n) into both the header names and values. While the specification states that \r\n\r\n is used to terminate the header list, many servers in the wild will also accept \n\n. An attacker that is able to control the header names that are passed to Slilm-Psr7 would be able to intentionally craft invalid messages, possibly causing application errors or invalid HTTP requests being sent out with an PSR-18 HTTP client. The latter might present a denial of service vector if a remote service’s web application firewall bans the application due to the receipt of malformed requests. The issue has been patched in version 1.6.1. There are no known workarounds to this issue. Users are advised to upgrade.

CVSS v3
6.5
EG Score
6.5(medium)
EPSS
50.9%
KEV
Not listed

Published

April 17, 2023

Last Modified

November 21, 2024

References (6)

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
slim/psr70.1.0 ... 1.4 (11 versions)1.4.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 48× 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.

Showing the most recent 100 of 104 total refreshes for this CVE.

  1. 2026-07-22 14:06 UTCEPSS rescore
  2. 2026-07-22 14:06 UTCEPSS rescore
  3. 2026-07-21 15:23 UTCEPSS rescore
  4. 2026-07-20 17:06 UTCEPSS rescore
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  13. 2026-07-15 23:19 UTCOSV refresh
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  1. 2026-07-09 19:08 UTCEPSS rescore
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  44. 2026-06-10 22:17 UTCEPSS rescore
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  47. 2026-06-10 10:17 UTCOSV refresh
  48. 2026-06-08 14:15 UTCEPSS rescore
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  50. 2026-06-07 15:23 UTCEPSS rescore
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  74. 2026-05-26 13:43 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2023-30536?
CVE-2023-30536 is a medium vulnerability published on April 17, 2023. slim/psr7 is a PSR-7 implementation for use with Slim 4. In versions prior to 1.6.1 an attacker could sneak in a newline (\n) into both the header names and values. While the specification states that \r\n\r\n is used to terminate the header list, many servers in the wild will also accept \n\n. An…
When was CVE-2023-30536 disclosed?
CVE-2023-30536 was first published in the National Vulnerability Database on April 17, 2023, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-30536 actively exploited?
CVE-2023-30536 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 50.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2023-30536?
CVE-2023-30536 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2023-30536?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-30536, 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.

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