Bug 2539085 (CVE-2026-91777)

Summary:	CVE-2026-91777 com.fasterxml.jackson.core/jackson-databind: Jackson-databind: Denial of Service via quadratic forward-reference completion
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:	aakkiang, abrianik, alinfoot, amctagga, anthomas, ant, anujha, aoconnor, aschwart, asoldano, asyoung, aszczucz, ataylor, bbaranow, bbrownin, bmaxwell, bniver, boliveir, bstansbe, ccranfor, cescoffi, cfu, cmah, csuconic, csutherl, dbruscin, dfreiber, dhanak, dlofthou, drichtar, drosa, drow, dschmidt, dsimansk, dsoumis, dtrifiro, ebaron, edewata, ehelms, ehugonne, ewittman, flucifre, fmariani, fmongiar, gbenhaim, ggainey, ggrzybek, gkimetto, gmalinko, gmeno, groman, gsmet, gtanzill, gtully, ikhan, istudens, ivassile, iweiss, janstey, jburrell, jbuscemi, jclere, jhollowa, jlanda, jmagne, jmartisk, jnethert, jpasqual, jpechane, jraez, jsherman, juwatts, jwon, kaycoth, kingland, kshier, kvanderr, manderse, mbenjamin, mcarlett, mdellweg, mfargett, mhackett, mhulan, mnovotny, mosmerov, mposolda, msvehla, nipatil, niyer, nmoumoul, nwallace, olubyans, osousa, ozzy, pantinor, parichar, pberan, pcreech, pdelbell, pesilva, pjindal, plodge, pmackay, prichard, prisingh, rbobbitt, rchan, rgemmell, rgodfrey, rguimara, rhel-process-autobot, rkubis, rmartinc, rmaucher, rstancel, rstepani, sausingh, sbiarozk, sdawley, simaishi, skhandel, smallamp, snegrini, sostapov, ssilvert, stcannon, sthirugn, sthorger, szappis, taherrin, tasato, tbish, tcunning, thjenkin, tlavocat, tmalecek, twaugh, varjain, vdosoudi, vereddy, vkumar, vmuzikar, watson-tool-maintainers, weaton, yfang, yguenane
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in FasterXML jackson-databind. This vulnerability allows a remote attacker to cause a Denial of Service (DoS) by providing specially crafted JSON input to an application that deserializes it into an identity-enabled collection or map. The flaw occurs due to inefficient processing of forward-references, where the system performs a quadratic amount of work for linearly growing input, leading to excessive CPU consumption.	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 2026-09-23 02:31:23 UTC

Forward-reference completion for @JsonIdentityInfo object IDs in FasterXML jackson-databind performs a linear scan of the pending-reference accumulator for every resolved ID. The affected paths are CollectionDeserializer.CollectionReferringAccumulator.resolveForwardReference() and the equivalent implementation in MapDeserializer. When a document first creates N unresolved object-ID references in an identity-enabled collection or map and then defines those same IDs in reverse order, completion performs on the order of N * (N + 1) / 2 identity comparisons, so a shallow document whose size grows linearly causes quadratic CPU work during deserialization. The reporter instrumented equals() calls on the ID class and measured exactly 2,003,000 comparisons at N = 2,000, against zero comparisons in the pending-reference lookup path for an equally sized control in which every reference was already resolved. The input requires no deep nesting and no syntactically unusual JSON. Exploitation requires an application that deserializes attacker-influenced JSON into an identity-enabled collection or map. The fix replaces the repeated linear lookup with a keyed pending-reference structure.