NLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView._read_xml_fragment() that rescans accumulated XML fragments on every 1 KiB block read. Attackers can provide malformed XML corpus files to cause severe CPU consumption and denial of service through affected readers like BNCCorpusReader.
CVE-2026-81723
LOWPre-NVD 3.73.7Trending — 3 sources updated this week
EchelonGraph scoreLOW confidence
This low-severity CVE scores 3.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: secondary
3.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 3.7Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 3.7
- EG Score
- 3.7(low)
- EG Risk
- 21(Track)EG Risk 21/100SSVC: Track
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 computedSeverity37% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 13%
- KEV
- Not listed
Published
August 27, 2026
Last Modified
August 27, 2026
References (2)
Vendor Advisories for CVE-2026-81723(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 5× in last 7d / 5× 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.
- 2026-08-30 01:22 UTCEPSS rescore
- 2026-08-28 21:42 UTCEPSS rescore
- 2026-08-27 17:24 UTCEG score recompute
- 2026-08-27 16:47 UTCEG score recompute
- 2026-08-27 16:43 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-400
Frequently asked(5)
What is CVE-2026-81723?
CVE-2026-81723 is a low vulnerability published on August 27, 2026. NLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView.readxml_fragment() that rescans accumulated XML fragments on every 1 KiB block read. Attackers can provide malformed XML corpus files to cause severe CPU consumption and denial of service through affected…
When was CVE-2026-81723 disclosed?
CVE-2026-81723 was first published in the National Vulnerability Database on August 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81723 actively exploited?
CVE-2026-81723 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 87.4% of all scored CVEs.
What is the CVSS score of CVE-2026-81723?
CVE-2026-81723 has a CVSS v3 base score of 3.7 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-81723?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81723, 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.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-81723
Is Your Infrastructure Affected by CVE-2026-81723?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.