CVE-2026-83619
highpriority · track · 0EPSS 0.005 · 44 %ileDENLRUUSEPSS · scored 2026-10-22
xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.7.0 until 0.8.15, the release-0.8.x parser in lib/sax.js trims captured end-tag names with the unanchored global expression /[ \t\n\r]+$/g. For an end tag containing a long whitespace run followed by a non-whitespace character, the expression retries from each possible starting position and backtracks quadratically before failing its end anchor. DOMParser.parseFromString() reaches the path under default options, allowing a small unauthenticated XML input to stall the Node.js event loop; the 0.9.x and unscoped npm lines do not contain this expression. This issue is fixed in @xmldom/xmldom version 0.8.15.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.6–8.7
ssvc
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weaknesses
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affected products (12)
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- IBM WebSphere Service Registry and Repositoryall versionscert_bundDEcpe:/a:ibm:websphere_service_registry_and_repository:-
advisories (4)
Vendor and ecosystem advisories describing this.
- NCSC-2026-0431Kwetsbaarheden verholpen in IBM DataPower Gateway en onderliggende componentenNL2026-10-16csaf · ncsc_nlNL
IBM heeft meerdere beveiligingsproblemen opgelost in DataPower Gateway versies 10.5 tot 11.0 en een veelvoud aan onderliggende subcomponenten.
- WID-SEC-W-2026-3596IBM App Connect Enterprise: Mehrere SchwachstellenDeutsch2026-09-27csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren und um einen Cross-Site Scripting Angriff durchzuführen.
- WID-SEC-W-2026-3623IBM DataPower Gateway: Mehrere SchwachstellenDeutsch2026-09-28csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM DataPower Gateway ausnutzen, um beliebigen Programmcode auszuführen, erweiterte Berechtigungen zu erlangen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren oder offenzulegen, einen Denial-of-Service-Zustand auszulösen oder Cross-Site-Scripting-Angriffe durchzuführen.
- GHSA-x4fp-j954-r2f4xmldom: End-tag Whitespace-Trim Regex ReDoS — quadratic backtracking in the 0.8.x end-tag parser2026-09-08ghsa · osvUS
## Summary On the `@xmldom/xmldom` **`0.8.x`** line, parsing an XML end tag whose name is followed by a long run of whitespace and then a non-whitespace character triggers quadratic-time regular-expression backtracking (ReDoS), so a single small crafted end tag stalls the Node.js event loop. It is reachable from `DOMParser.parseFromString` under **default options**, unauthenticated, before any validity check — an availability-only denial of service. The `0.9.x` line is **not** affected. ## Details `lib/sax.js` (release-0.8.x, commit `e5c1480`) trims trailing whitespace from a captured end-tag name with an unanchored global regex: - `lib/sax.js` line 120: https://github.com/xmldom/xmldom/blob/e5c14802592685bb872c042c54c3f73758875c85/lib/sax.js#L120 ```js /[ \t\n\r]+$/g ``` Applied to a string shaped `whitespace-run + one non-whitespace char` (e.g. the content of an end tag `</ … x>`), the engine must, for every starting position, extend `[ws]+` to the end and then fail the `$` anchor when the trailing non-whitespace char is present — classic O(n²) backtracking in the length of the whitespace run. The trimmed substring is delimited only by `indexOf('>')`, so the attacker controls its length directly. ## Proof of Concept ```js const { DOMParser } = require('@xmldom/xmldom'); // 0.8.x const n = 64 * 1024; const payload = '<r></' + ' '.repeat(n) + 'x>'; console.time('parse'); new DOMParser().parseFromString(payload, 'text/xml'); console.timeEnd('parse'); ``` Measured (Node 18) — time quadruples per doubling of the whitespace run (canonical O(n²)): | Whitespace run | Isolated regex | End-to-end `parseFromString` (0.8.13) | |---|---|---| | 4 KB | 5.6 ms | 5.7 ms | | 8 KB | 22.7 ms | 22.5 ms | | 16 KB | 88.6 ms | 92 ms | | 32 KB | 354 ms | 361 ms | | 64 KB | 1434 ms | 1452 ms | | 128 KB | 5761 ms | — | ## Impact Availability only: a single parse of a small crafted document blocks the Node.js event loop for the duration of the quadratic scan (≈1.4 s at 64 KB; multi-second with larger inputs). No memory blow-up, no data exposure, no integrity impact. Because XML is routinely accepted from untrusted sources and parsed with default options, one request can stall a server. ## Affected Versions Affected on the `0.7.x` and `0.8.x` lines (the trailing-whitespace trim was added in `0.7.0`, present through `0.8.14`); the fix targets the `0.8.x` LTS patch. The `0.9.x` line rewrote end-tag parsing to an anchored linear matcher and never had this regex, so it is **not** affected. No published unscoped `xmldom` is affected — the vulnerable code exists only in a `0.7.0` git tag that was never released to npm (`npm view xmldom` → `latest` = 0.6.0). ## Fix Applied Anchors the end-tag trailing-whitespace trim so it runs in linear time instead of backtracking quadratically on a long whitespace run. Byte-identical output. Non-breaking; 0.8.x-only. ## Severity note The complexity is **quadratic**, not exponential, so a multi-second stall requires tens-to-hundreds of KB of input. `VA:H` reflects that xmldom applies **no input-size limit** and the path runs on default-options parsing, so a single unbounded parse can fully stall the event loop.
also known as (1)
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references (4) nvd
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