CVE-2023-38697

MEDIUMNVD 5.85.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This medium-severity CVE scores 5.8 under NVD CVSS v3. EPSS exploit probability: 0.8% (54th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
5.8EG
EchelonGraph verdictMonitorRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 5.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

protocol-http1 provides a low-level implementation of the HTTP/1 protocol. RFC 9112 Section 7.1 defined the format of chunk size, chunk data and chunk extension. The value of Content-Length header should be a string of 0-9 digits, the chunk size should be a string of hex digits and should split from chunk data using CRLF, and the chunk extension shouldn't contain any invisible character. However, Falcon has following behaviors while disobey the corresponding RFCs: accepting Content-Length header values that have + prefix, accepting Content-Length header values that written in hexadecimal with 0x prefix, accepting 0x and + prefixed chunk size, and accepting LF in chunk extension. This behavior can lead to desync when forwarding through multiple HTTP parsers, potentially results in HTTP request smuggling and firewall bypassing. This issue is fixed in protocol-http1 v0.15.1. There are no known workarounds.

CVSS v3
5.8
EG Score
5.8MEDIUMmedium confidence
EG Risk
41
EG Risk 41/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity58% × 45%
Impact severity (EG Severity): CVSS 5.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.8% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.8%
EPSS %ILE
54th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.8): severity, escalated by confirmed exploitation. This CVE's 5.8 is its impact severity (EG Severity), not escalated.

EG Severity
5.8 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.8% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 4, 2023

Last Modified

November 21, 2024

References (4)

Vendor Advisories for CVE-2023-38697(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-protocol-http10.13.1-1 ... 0.40.0-1 (9 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-protocol-http10.14.6-1 ... 0.41.0-1 (6 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-protocol-http10.12.0-1 ... 0.14.6-1 (9 versions)
  • every version up to 0.35.2-1: fixed in 0.35.2-1
—
RubyGems(1)
PackageVulnerable rangeFix by version rangeDependents
protocol-http10.1.0 ... 0.9.0 (30 versions)
  • every version up to 0.15.1: fixed in 0.15.1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 34× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 94 of 200 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 6 repeat rows among the latest 100 are merged into the row they repeat. The 106 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-21 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  2. 2026-10-20 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  3. 2026-10-19 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  4. 2026-10-18 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  5. 2026-10-18 07:55 UTCEG score recompute
  6. 2026-10-17 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  7. 2026-10-16 16:35 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  8. 2026-10-15 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  9. 2026-10-14 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  10. 2026-10-13 16:30 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  11. 2026-10-13 07:54 UTCOSV refresh
  12. 2026-10-12 18:22 UTCEG score recompute
  13. 2026-10-12 16:30 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  14. 2026-10-11 21:48 UTCEG score recompute
  15. 2026-10-11 13:45 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  16. 2026-10-10 19:57 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  17. 2026-10-09 20:05 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  18. 2026-10-08 17:06 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  19. 2026-10-07 23:46 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  20. 2026-10-06 15:15 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  21. 2026-10-05 17:41 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  22. 2026-10-04 23:20 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  23. 2026-10-03 14:23 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  24. 2026-09-30 16:27 UTCEG score recompute
  25. 2026-09-30 15:01 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
Show 69 more
  1. 2026-09-29 15:16 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  2. 2026-09-28 13:49 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  3. 2026-09-27 13:42 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  4. 2026-09-26 15:55 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  5. 2026-09-26 00:22 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  6. 2026-09-24 14:01 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  7. 2026-09-23 13:45 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  8. 2026-09-23 03:02 UTCOSV refresh
  9. 2026-09-22 14:45 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  10. 2026-09-20 20:14 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  11. 2026-09-16 14:05 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  12. 2026-09-13 16:44 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  13. 2026-09-12 14:58 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  14. 2026-09-11 14:50 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  15. 2026-09-11 09:34 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  16. 2026-09-08 21:57 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  17. 2026-09-07 15:59 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  18. 2026-09-06 13:45 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  19. 2026-09-05 15:26 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  20. 2026-09-04 13:58 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  21. 2026-09-04 05:04 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  22. 2026-09-03 21:59 UTCOSV refresh
  23. 2026-09-02 14:09 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  24. 2026-09-01 13:51 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  25. 2026-08-30 19:15 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  26. 2026-08-30 01:20 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  27. 2026-08-28 21:38 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  28. 2026-08-27 14:23 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  29. 2026-08-26 14:43 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  30. 2026-08-25 13:46 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  31. 2026-08-24 14:14 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  32. 2026-08-23 00:17 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  33. 2026-08-21 23:47 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  34. 2026-08-20 22:53 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  35. 2026-08-19 17:02 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  36. 2026-08-18 13:46 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  37. 2026-08-17 13:45 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  38. 2026-08-17 11:16 UTCOSV refresh
  39. 2026-08-16 14:54 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  40. 2026-08-16 02:12 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  41. 2026-08-15 01:28 UTCEPSS rescoreEPSS 0.8% · 51st percentile
  42. 2026-08-13 21:58 UTCEPSS rescoreEPSS 0.8% · 51st percentile
  43. 2026-08-12 13:48 UTCEPSS rescoreEPSS 0.8% · 51st percentile
  44. 2026-08-11 13:39 UTCEPSS rescoreEPSS 0.8% · 51st percentile
  45. 2026-08-09 13:44 UTCEPSS rescoreEPSS 0.8% · 51st percentile
  46. 2026-08-08 16:34 UTCEPSS rescoreEPSS 0.8% · 51st percentile
  47. 2026-08-07 16:24 UTCEPSS rescoreEPSS 0.8% · 51st percentile
  48. 2026-08-06 13:44 UTCEPSS rescoreEPSS 0.8% · 51st percentile
  49. 2026-08-05 19:15 UTCEPSS rescoreEPSS 0.8% · 51st percentile
  50. 2026-08-04 15:07 UTCEPSS rescoreEPSS 0.8% · 51st percentile
  51. 2026-08-04 10:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  52. 2026-08-03 10:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  53. 2026-08-02 05:58 UTCOSV refresh
  54. 2026-08-02 02:25 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  55. 2026-08-01 04:13 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  56. 2026-07-30 16:26 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  57. 2026-07-30 01:28 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  58. 2026-07-28 15:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  59. 2026-07-27 14:10 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  60. 2026-07-26 14:52 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  61. 2026-07-25 14:16 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  62. 2026-07-24 14:16 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  63. 2026-07-23 14:16 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  64. 2026-07-23 02:25 UTCEG score recompute
  65. 2026-07-22 23:11 UTCEG score recompute
  66. 2026-07-22 14:06 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  67. 2026-07-21 15:23 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  68. 2026-07-20 17:06 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  69. 2026-07-19 14:29 UTCEPSS rescoreEPSS 0.6% · 46th percentile

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2023-38697?
CVE-2023-38697 is a medium-severity vulnerability; its CVE record was published on August 4, 2023. protocol-http1 provides a low-level implementation of the HTTP/1 protocol. RFC 9112 Section 7.1 defined the format of chunk size, chunk data and chunk extension. The value of Content-Length header should be a string of 0-9 digits, the chunk size should be a string of hex digits and should split…
When was the CVE record for CVE-2023-38697 published?
The CVE record for CVE-2023-38697 was published on August 4, 2023. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 21, 2024; the record at its source may have been updated since.
Is CVE-2023-38697 actively exploited?
CVE-2023-38697 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (54th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2023-38697?
CVE-2023-38697 has a CVSS v3 base score of 5.8 (NVD).
How do I remediate CVE-2023-38697?
A fix for CVE-2023-38697 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2023-38697 are linked in the Vendor Advisories panel on this page.

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