CVE-2026-3634

MEDIUMNVD 6.56.5
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.2% (8th percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 3.9 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2026-03-17) is not newer than that change (2026-06-17), so it does not.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Elevated

Also known asEUVD-2026-12561 (ENISA EUVD) · GHSA-jx6g-363c-pprr (GitHub Security Advisories)Source: ENISA EUVD

6.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

A flaw was found in libsoup. An attacker controlling the value used to set the Content-Type header can inject a Carriage Return Line Feed (CRLF) sequence due to improper input sanitization in the soup_message_headers_set_content_type() function. This vulnerability allows for the injection of arbitrary header-value pairs, potentially leading to HTTP header injection and response splitting attacks.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
45
EG Risk 45/100

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)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (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.
EPSS PROB
0.2%
EPSS %ILE
8th
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 (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 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
0.2% within 30 daysSource: FIRST EPSS. 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; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

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

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (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

March 17, 2026

Last Modified

June 17, 2026

Advisory Details (3)

Auto-updated Aug 4, 2026
Patch available. Sources: redhat.
Web page

(CVE-2026-3634) libsoup: CRLF injection in `soup_message_headers_set_content_type()` (#485) · Issues · GNOME / libsoup · GitLab

https://gitlab.gnome.org/GNOME/libsoup/-/issues/485
Red Hat

2445129 – (CVE-2026-3634) CVE-2026-3634 libsoup: libsoup: HTTP header injection and response splitting via CRLF injection in Content-Type header

https://bugzilla.redhat.com/show_bug.cgi?id=2445129
Red HatMentions a patch (unverified)

CVE-2026-3634 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-3634

Vendor Advisories for CVE-2026-3634(1)

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

Affected Packages

(6 across 4 ecosystems)
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
libsoup2.42.74.3-1 ... 2.74.3-9 (16 versions)
  • every version on: no fix on record
—
libsoup33.2.2-2 ... 3.6.6-1 (35 versions)
  • every version on: no fix on record
—
Debian:13(2)
PackageVulnerable rangeFix by version rangeDependents
libsoup2.42.74.3-10.1, 2.74.3-11
  • every version on: no fix on record
—
libsoup33.6.5-3 ... 3.6.6-1 (8 versions)
  • every version on: no fix on record
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
libsoup2.42.72.0-2 ... 2.74.3-9 (28 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libsoup33.6.5-3 ... 3.6.6-1 (8 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 37× 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 99 of 114 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. 1 repeat row among the latest 100 is merged into the row it repeats. The 15 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  2. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  3. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  4. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  5. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  6. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  7. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  8. 2026-10-25 14:32 UTCEG score recompute
  9. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  10. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  11. 2026-10-23 02:57 UTCEG score recompute
  12. 2026-10-23 02:57 UTCVendor advisory
  13. 2026-10-23 02:56 UTCGHSA enrichmentGHSA-jx6g-363c-pprr · GitHub severity LOW · GitHub CVSS 3.9
  14. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  15. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  16. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  17. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  18. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  19. 2026-10-18 03:44 UTCEG score recompute
  20. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  21. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  22. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  23. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  24. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  25. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 21st percentile
Show 74 more
  1. 2026-10-12 16:11 UTCEG score recompute
  2. 2026-10-11 19:53 UTCEG score recompute
  3. 2026-10-11 17:06 UTCEG score recompute
  4. 2026-10-11 14:33 UTCEG score recompute
  5. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  6. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  7. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  8. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  9. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  10. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  11. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  12. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  13. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  14. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  15. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  16. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  17. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  18. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  19. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  20. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  21. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  22. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  23. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  24. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  25. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  26. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  27. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  28. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  29. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  30. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  31. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  32. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  33. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  34. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  35. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  36. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  37. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  38. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  39. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  40. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  41. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  42. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  43. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  44. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  45. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  46. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  47. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  48. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  49. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  50. 2026-08-16 11:22 UTCEG score recompute
  51. 2026-08-16 11:22 UTCGHSA enrichmentGHSA-jx6g-363c-pprr · GitHub severity LOW · GitHub CVSS 3.9
  52. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  53. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  54. 2026-08-14 07:29 UTCEG score recompute
  55. 2026-08-14 07:29 UTCGHSA enrichmentGHSA-jx6g-363c-pprr · GitHub severity LOW · GitHub CVSS 3.9
  56. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  57. 2026-08-12 22:16 UTCEG score recompute
  58. 2026-08-12 22:16 UTCGHSA enrichmentGHSA-jx6g-363c-pprr · GitHub severity LOW · GitHub CVSS 3.9
  59. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  60. 2026-08-11 13:43 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  61. 2026-08-11 04:41 UTCEG score recompute
  62. 2026-08-11 04:41 UTCGHSA enrichmentGHSA-jx6g-363c-pprr · GitHub severity LOW · GitHub CVSS 3.9
  63. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  64. 2026-08-10 05:50 UTCEG score recompute
  65. 2026-08-10 05:50 UTCGHSA enrichmentGHSA-jx6g-363c-pprr · GitHub severity LOW · GitHub CVSS 3.9
  66. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  67. 2026-08-09 07:04 UTCEG score recompute
  68. 2026-08-09 07:04 UTCGHSA enrichmentGHSA-jx6g-363c-pprr · GitHub severity LOW · GitHub CVSS 3.9
  69. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  70. 2026-08-07 17:42 UTCEG score recompute
  71. 2026-08-07 17:42 UTCGHSA enrichmentGHSA-jx6g-363c-pprr · GitHub severity LOW · GitHub CVSS 3.9
  72. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  73. 2026-08-06 01:43 UTCEG score recompute
  74. 2026-08-06 01:43 UTCGHSA enrichmentGHSA-jx6g-363c-pprr · GitHub severity LOW · GitHub CVSS 3.9

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-3634?
CVE-2026-3634 is a medium-severity vulnerability; its CVE record was published on March 17, 2026. A flaw was found in libsoup. An attacker controlling the value used to set the Content-Type header can inject a Carriage Return Line Feed (CRLF) sequence due to improper input sanitization in the soup_message_headers_set_content_type() function. This vulnerability allows for the injection of…
When was CVE-2026-3634 made public?
CVE-2026-3634 was made public on March 6, 2026: that is the date its CVE record's CNA, Red Hat, Inc., gives for when the vulnerability was made public. The CVE record itself was published on March 17, 2026. EchelonGraph's copy of the record carries a last-modified date of June 17, 2026; the record at its source may have been updated since.
Is CVE-2026-3634 actively exploited?
CVE-2026-3634 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (8th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-3634?
CVE-2026-3634 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-3634?
A fix for CVE-2026-3634 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-3634 are linked in the Vendor Advisories panel on this page.

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