CVE-2026-55798

MEDIUMPre-NVD 4.54.5
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 4.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (7th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated

Also known asEUVD-2026-41898 (ENISA EUVD) · GHSA-4x4j-2g7c-83w6 (GitHub Security Advisories)Source: ENISA EUVD

4.5EG
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: 4.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Pillow is a Python imaging library. Prior to 12.3.0, WindowsViewer.get_command() constructed a cmd.exe shell command by directly embedding a file path into an f-string without escaping and passed the result to subprocess.Popen(..., shell=True), allowing shell metacharacters in the file path to inject arbitrary cmd.exe commands. This issue is fixed in version 12.3.0.

CVSS v3
4.5
EG Score
4.5MEDIUMmedium confidence
EG Risk
36
EG Risk 36/100

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)
Severity45% × 45%
Impact severity (EG Severity): CVSS 4.5 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
7th
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 (4.5): severity, escalated by confirmed exploitation. This CVE's 4.5 is its impact severity (EG Severity), not escalated.

EG Severity
4.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-25). 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: 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.

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

July 6, 2026

Last Modified

October 25, 2026

Advisory Details (5)

Auto-updated Jul 7, 2026
Patch available. Sources: github_commit, github.
GitHub advisoryMentions a patch (unverified)

WindowsViewer.get_command() OS command injection via unescaped shell path (CWE-78) · Advisory · python-pillow/Pillow · GitHub

https://github.com/python-pillow/Pillow/security/advisories/GHSA-4x4j-2g7c-83w6
GitHub commit Patch Available

commit b0e06caa64c1 (python-pillow/Pillow)

Patch available: python-pillow/Pillow 12.3.0 (contains commit b0e06caa64c1)

https://github.com/python-pillow/Pillow/commit/b0e06caa64c1405aa3da0bb1d2bd9a77ca22de7f
GitHub commit Patch Available

commit 88194166691b (python-pillow/Pillow)

Patch available: python-pillow/Pillow 12.3.0 (contains commit 88194166691b)

https://github.com/python-pillow/Pillow/commit/88194166691b7b603529b8b036ab3ab9cedd2de4
GitHub commit Patch Available

commit 8404ea5fe5df (python-pillow/Pillow)

Patch available: python-pillow/Pillow 12.3.0 (contains commit 8404ea5fe5df)

https://github.com/python-pillow/Pillow/commit/8404ea5fe5df40fc34aa1e51403dd6fce0778b8a
Web page

Pillow/docs/releasenotes/12.3.0.rst at main · python-pillow/Pillow · GitHub

https://github.com/python-pillow/Pillow/blob/main/docs/releasenotes/12.3.0.rst

Vendor Advisories for CVE-2026-55798(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 rangeFix by version rangeDependents
pillow1.0 ... 9.5.0 (106 versions)
  • every version up to 12.3.0: fixed in 12.3.0
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 38× 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 100 of 147 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. None are among the latest 100 rows. The 47 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  2. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  3. 2026-10-25 20:27 UTCEG score recompute
  4. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  5. 2026-10-25 14:18 UTCEG score recompute
  6. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  7. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  8. 2026-10-22 21:13 UTCEG score recompute
  9. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  10. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  11. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  12. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  13. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  14. 2026-10-18 03:29 UTCEG score recompute
  15. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  16. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  17. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  18. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  19. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  20. 2026-10-13 13:54 UTCOSV refresh
  21. 2026-10-12 15:55 UTCEG score recompute
  22. 2026-10-11 19:38 UTCEG score recompute
  23. 2026-10-11 16:53 UTCEG score recompute
  24. 2026-10-11 14:16 UTCEG score recompute
  25. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.2% · 6th percentile
Show 75 more
  1. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  2. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  3. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  4. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  5. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  6. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  7. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  8. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  9. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  10. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  11. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  12. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  13. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  14. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  15. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  16. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  17. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  18. 2026-09-23 06:23 UTCEG score recompute
  19. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  20. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  21. 2026-09-18 06:00 UTCEG score recompute
  22. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  23. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  24. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  25. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  26. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  27. 2026-09-13 16:46 UTCEG score recompute
  28. 2026-09-12 13:37 UTCEG score recompute
  29. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  30. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  31. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  32. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  33. 2026-09-05 23:11 UTCEG score recompute
  34. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  35. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  36. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  37. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  38. 2026-08-30 08:14 UTCEG score recompute
  39. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  40. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  41. 2026-08-28 04:31 UTCEG score recompute
  42. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  43. 2026-08-27 02:16 UTCEG score recompute
  44. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  45. 2026-08-25 14:52 UTCEG score recompute
  46. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  47. 2026-08-24 13:18 UTCEG score recompute
  48. 2026-08-22 10:10 UTCEG score recompute
  49. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  50. 2026-08-21 08:36 UTCEG score recompute
  51. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  52. 2026-08-20 07:01 UTCEG score recompute
  53. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  54. 2026-08-19 05:28 UTCEG score recompute
  55. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  56. 2026-08-18 03:48 UTCEG score recompute
  57. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  58. 2026-08-17 00:05 UTCEG score recompute
  59. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  60. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  61. 2026-08-15 22:31 UTCEG score recompute
  62. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  63. 2026-08-14 20:55 UTCEG score recompute
  64. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  65. 2026-08-12 17:46 UTCEG score recompute
  66. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  67. 2026-08-11 16:13 UTCEG score recompute
  68. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  69. 2026-08-10 14:39 UTCEG score recompute
  70. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  71. 2026-08-09 13:05 UTCEG score recompute
  72. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.2% · 7th percentile
  73. 2026-08-08 11:32 UTCEG score recompute
  74. 2026-08-07 09:56 UTCEG score recompute
  75. 2026-08-06 13:47 UTCEPSS rescoreEPSS 0.2% · 7th percentile

Frequently asked(5)

What is CVE-2026-55798?
CVE-2026-55798 is a medium-severity vulnerability; its CVE record was published on July 6, 2026. Pillow is a Python imaging library. Prior to 12.3.0, WindowsViewer.get_command() constructed a cmd.exe shell command by directly embedding a file path into an f-string without escaping and passed the result to subprocess.Popen(..., shell=True), allowing shell metacharacters in the file path to…
When was the CVE record for CVE-2026-55798 published?
The CVE record for CVE-2026-55798 was published on July 6, 2026. 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 October 25, 2026; the record at its source may have been updated since.
Is CVE-2026-55798 actively exploited?
CVE-2026-55798 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (7th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55798?
CVE-2026-55798 has a CVSS base score of 4.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55798?
A fix for CVE-2026-55798 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55798 are linked in the Vendor Advisories panel on this page.

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