MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's get_pac_princ_with_realm() that returns success while leaving the client principal NULL on malformed names. A malicious or compromised cross-realm trusted KDC can send an S4U2Proxy request with a PAC carrying a malformed client name to crash krb5kdc and deny authentication.
CVE-2026-107708
MEDIUMPre-NVD 4.94.9Trending — 5 sources updated this week
EchelonGraph scoreHIGH confidence
“—” beside the score: it is equal to the CVSS score beside it.
Score 4.9 from GitHub Security Advisory published 2026-10-08. A secondary CVSS source baseline 4.9; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
4.9EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 4.9Exploit: None knownExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 4.9
- EG Score
- 4.9MEDIUMhigh confidence
- EG Risk
- 22EG Risk 22/100
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 (value × EchelonGraph’s weight)Severity49% × 45%The EG Score, 4.9 of 10.Exploitation0.5% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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
- 0.5%
- EPSS %ILE
- 42nd
- KEV
- Not listed
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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
October 8, 2026
Last Modified
October 8, 2026
Advisory Details (6)
Auto-updated Oct 8, 2026Patch available. Sources: github_pr, github_commit.
Web page
MIT krb5 through 1.22.2 KDC NULL Pointer Dereference via S4U2Proxy PAC | Advisories | VulnCheck
https://www.vulncheck.com/advisories/mit-krb5-through-1.22.2-kdc-null-pointer-dereference-via-s4u2proxy-pacWeb page
krb5/src/kdc/kdc_util.c at krb5-1.22.2-final · krb5/krb5 · GitHub
https://github.com/krb5/krb5/blob/krb5-1.22.2-final/src/kdc/kdc_util.c#L639-L676GitHub commit
commit a88a18cafa10 (krb5/krb5)
Fix landed in krb5/krb5 commit a88a18cafa10 — awaiting tagged release
https://github.com/krb5/krb5/commit/a88a18cafa1040a0c4f9c8d08288fc98831ec86dGitHub commit
commit f6e2c397ceda (krb5/krb5)
Fix landed in krb5/krb5 commit f6e2c397ceda — awaiting tagged release
https://github.com/krb5/krb5/commit/f6e2c397ceda6467ebbaab8ed66d4895c9f1d6a7GitHub pull request
Fix error propagation in get_pac_princ_with_realm
Fix merged in krb5/krb5 PR #1510 on 2026-05-19 — awaiting tagged release
https://github.com/krb5/krb5/pull/1510Vendor Advisories for CVE-2026-107708(2)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(3 across 3 ecosystems)
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| krb5 | 1.20.1-2 ... 1.22.1-3 (23 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| krb5 | 1.21.3-5 ... 1.22.1-3 (6 versions) |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| krb5 | 1.21.3-5, 1.22.1-1, 1.22.1-2, 1.22.1-2.1, 1.22.1-3 |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 19× in last 7d / 19× 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.
- 2026-10-12 16:38 UTCEG score recompute
- 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-11 23:11 UTCVendor advisory
- 2026-10-11 23:10 UTCGHSA enrichmentGHSA-wc3c-9xc9-26g8 · GitHub CVSS 4.9
- 2026-10-11 20:14 UTCEG score recompute
- 2026-10-11 18:26 UTCEG score recompute
- 2026-10-11 15:00 UTCEG score recompute
- 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-10 22:40 UTCEG score recompute
- 2026-10-10 22:40 UTCGHSA enrichmentGHSA-wc3c-9xc9-26g8 · GitHub CVSS 4.9
- 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-09 22:10 UTCEG score recompute
- 2026-10-09 22:09 UTCGHSA enrichmentGHSA-wc3c-9xc9-26g8 · GitHub CVSS 4.9
- 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-10-08 21:37 UTCEG score recompute
- 2026-10-08 21:37 UTCGHSA enrichmentGHSA-wc3c-9xc9-26g8 · GitHub CVSS 4.9
- 2026-10-08 21:20 UTCEG score recompute
- 2026-10-08 20:23 UTCEG score recomputeFirst assessed: 4.9 MEDIUM
- 2026-10-08 20:23 UTCMITRE cvelistV5first tracked
Related CVEs(same product + same CWE)
Same product
10 shownDebian:12:krb5
- CVE-2011-4862EG 10.0EPSS p100HIGH
- CVE-2011-0285EG 10.0EPSS p97HIGH
- CVE-2009-4212EG 10.0EPSS p94HIGH
- CVE-2009-0846EG 10.0EPSS p95HIGH
- CVE-2008-0947EG 10.0EPSS p95HIGH
- CVE-2007-5902EG 10.0EPSS p93HIGH
- CVE-2007-4743EG 10.0EPSS p91HIGH
- CVE-2007-3999EG 10.0EPSS p96HIGH
- CVE-2007-2442EG 10.0EPSS p96HIGH
- CVE-2007-0956EG 10.0EPSS p98HIGH
Frequently asked(5)
What is CVE-2026-107708?
CVE-2026-107708 is a medium-severity vulnerability; its CVE record was published on October 8, 2026. MIT krb5 through 1.22.2 contains a NULL pointer dereference vulnerability in the KDC's getpacprincwithrealm() that returns success while leaving the client principal NULL on malformed names. A malicious or compromised cross-realm trusted KDC can send an S4U2Proxy request with a PAC carrying a…
When was CVE-2026-107708 made public?
CVE-2026-107708 was made public on May 19, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on October 8, 2026. EchelonGraph's copy of the record carries a last-modified date of October 8, 2026; the record at its source may have been updated since.
Is CVE-2026-107708 actively exploited?
CVE-2026-107708 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (42nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-107708?
CVE-2026-107708 has a CVSS base score of 4.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-107708?
A fix for CVE-2026-107708 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-107708 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-107708
Is Your Infrastructure Affected by CVE-2026-107708?
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