Bug 2567437 (CVE-2026-78661)

Summary:	CVE-2026-78661 golang.org/x/net/html: golang.org/x/net/html: Denial of Service via crafted HTML input
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	aazores, abarbaro, akhatavk, akostadi, akoudelk, alebedev, alizardo, amasferr, amctagga, anjoseph, anpicker, ansmith, aoconnor, aos-team-art-private, asdas, blitton, bniver, ckandaga, cmah, cmyers, crizzo, dakwon, dhanak, dkeler, dmayorov, dnakabaa, doconnor, dpaolell, drosa, dsimansk, dymurray, eaguilar, ebaron, eborisov, eglynn, ehelms, flucifre, gbenhaim, gmeno, gparvin, groman, hasun, ibolton, jbalunas, jbritton, jburrell, jcantril, jchui, jdelft, jeder, jfula, jhe, jjoyce, jlanda, jlledo, jmatsuok, jmatthew, jmontleo, jowilson, jpasqual, jprabhak, jpretori, jschluet, jtolenti, jupierce, juwatts, kaycoth, kingland, kshier, ktsao, lball, lblicha, lbragsta, lchilton, lcouzens, lgamliel, lgarciaa, lhh, mbarnett, mbenjamin, mbiarnes, mburns, mgarciac, mhackett, mhulan, mnovotny, mwringe, nboldt, ngough, niyer, nyancey, oaljalju, ogajduse, ometelka, osousa, pantinor, pgaikwad, pjindal, ppalepu, ppostler, prdhamdh, psrna, ptisnovs, pvasanth, rbobbitt, rchan, rekumar, rhaigner, rhel-process-autobot, rjohnson, rojacob, sakbas, sausingh, sbratsla, sdawley, sfeifer, sghai, sidsharm, simaishi, slucidi, smallamp, sostapov, sseago, stcannon, suppawar, syedriko, thason, tsedmik, tsze, twaugh, tzivkovi, vereddy, veshanka, vkarehfa, vlaad, vvoronko, watson-tool-maintainers, wenshen, whayutin, wtam, xdharmai, yguenane, zhunting
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in golang.org/x/net/html. A remote attacker can cause a Denial of Service (DoS) by providing specially crafted HTML input containing numerous short text fragments separated by ignored tags. When combining adjacent text nodes, the parser repeatedly reallocates and copies memory for each segment. This inefficient processing causes excessive CPU and memory consumption, potentially leading to application slowdowns or crashes.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-11-05 21:57:40 UTC

When coalescing adjacent text nodes in addText and fosterParent, appending to an existing TextNode's Data via string concatenation (n.Data += text) reallocated and copied the accumulated string on every token. Inputs containing many short text runs separated by ignored end tags (such as "a</x>") caused O(n^2) allocations and byte copies. Accumulate coalesced text in per-node byte slices during parsing and materialize Data strings once at the end of parse.